Diastasis recti abdominis Updated 2026

Clinical synthesis on postnatal diastasis recti abdominis (DRA): measurement, rehabilitation and controversies, based on recent studies. Every reference has been verified on PubMed.

🤰 What are the fundamentals to know about diastasis recti abdominis?

Diastasis recti abdominis is probably one of the topics where the gap between everyday clinical talk and the available data is widest. It is readily presented as a lesion to be closed, a cause of low back pain, a factor in urinary leakage, and its management comes bundled with lists of forbidden exercises. Yet the literature says something else: it is an extremely common adaptation to pregnancy, largely self-resolving, whose link with lumbopelvic pain and pelvic floor dysfunction is not established, but whose impact on body image and quality of life is real and underestimated. This section sets out the essential reference points before any rehabilitation decision: definition, measurement, epidemiology, anatomy of the linea alba, and the mechanisms of distension.

Definition: a measured widening of the linea alba, to be distinguished from hernia

Diastasis recti abdominis (DRA, diastasis recti abdominis) is defined by measurement: it is the increase in the distance separating the two rectus abdominis muscles either side of the linea alba: the inter-recti distance, or IRD (inter-recti distance). All the landmark studies diagnose it this way, by a palpated separation ¹ or by an ultrasound IRD exceeding a threshold ²⁴³. This is a point of vocabulary with direct consequences in clinic: a patient who hears “separation” or “gap” often understands “tear”, whereas what is measured is a distance, and diastasis is, as we shall see, the usual situation at the end of pregnancy.

In the landmark study in this field, the Norwegian prospective cohort of 300 primiparous women followed from pregnancy to one year postnatally, diastasis is defined as a palpated separation of at least 2 fingerbreadths, assessed at three levels: 4,5 cm above the umbilicus, at the umbilicus, and 4,5 cm below, with the patient supine performing an abdominal crunch ¹. Note this triple location straight away: measurement is not taken at a single point, but above and below the umbilicus: a diastasis may be present at only one level.

Diastasis must be distinguished from hernia of the linea alba, which is a different entity and a frequent comorbidity. In a multicentre retrospective study of 1 294 cases of diastasis followed over 10 years, 35,8 % of women and 56,1 % of men had one or more hernias (p < 0,001), umbilical hernia being the most prominent type; in women, age (OR 1,51 [1,33–1,72]; p = 0,000) and smoking (OR 1,66 [1,13–2,44]; p = 0,010) were risk factors for an associated hernia ⁴. This screening is not cosmetic: in 231 patients operated on for a small umbilical or epigastric hernia (< 2 cm) by simple suture, the recurrence rate reached 31,2 % (29/93) when an associated diastasis was present, versus 8,3 % (9/108) in its absence (p < 0,001), leading the authors to strongly recommend systematic preoperative screening for diastasis ⁵. A painful or irreducible midline bulge therefore calls for medical and surgical advice, not for watchful waiting in rehabilitation.

Strong evidence Finally, the definition must include from the outset what diastasis is not. In the Sperstad cohort, the presence of a diastasis at 12 months postnatally was not associated with more lumbopelvic pain: no significant difference between women with and without diastasis (p = 0,10) ¹. Diastasis should therefore not be presented straight away as the cause of postnatal low back pain.

Measuring the IRD: is the finger enough? And where should you measure?

Measurement is not a methodological detail: it determines the diagnosis, the follow-up, and above all the critical reading of the literature. A systematic review of methods for measuring diastasis (13 studies evaluating fingerbreadth, tape measure, callipers, ultrasound, CT and MRI) concludes that ultrasound and callipers are the adequate methods for assessing diastasis, with low measurement error above the umbilicus; the fingerbreadth method, by contrast, offers only moderate inter-rater agreement: 63 %, weighted Kappa = 0,53 ⁶.

Moderate evidence The most counter-intuitive point concerns the location of the measurement. Ultrasound reliability depends strongly on the site: excellent above the umbilicus, poor at the umbilical level itself. At rest, the ICC reaches 0,91 at 5 cm above the umbilicus but falls to 0,72 at the upper edge of the umbilicus ; on head lift, it goes from 0,96 (5 cm above) to 0,63 at the umbilical level. The authors' practical recommendation: favour standardised supra-umbilical measurement sites ⁷. A clinical paradox to take on board: it is precisely at the umbilicus that the gap is widest, the maximum separation was located there in women with diastasis (4,59 ± 1,14 cm) ²⁷, and that is where the measurement is least reliable.

This is consistent with the reproducibility data for 2D ultrasound: good to very good test-retest reliability (ICC between 0,74 and 0,90), with the single exception of the measurement 2 cm below the umbilicus during the crunch (ICC 0,50) ; intra-observer reproducibility on the same images exceeds 0,90 ⁹. In other words: ultrasound is reliable, but not everywhere and not in every position.

What reference values? The single 2 cm threshold does not hold

To interpret an IRD, you first need to know what a “normal” linea alba is. In healthy nulliparous women, a meta-analysis establishes that the maximum IRD reported on ultrasound is below 10 mm at every location, with pooled values of approximately 8,77 mm in the umbilical zone, 7,22 mm in the epigastric zone and 4,09 mm in the infra-umbilical zone ¹¹. The normal value is therefore not a single figure: it varies twofold depending on the level measured.

< 10 mmMaximum IRD reported in healthy nulliparous women, at every location ¹¹

Moderate evidence In primiparous women the reference shifts. In the longitudinal ultrasound follow-up of 84 primiparous women, the 20^th and 80^th percentiles of the IRD at 6 months postnatally were 9–21 mm at 2 cm below the umbilicus, 17–28 mm at 2 cm above and 12–24 mm at 5 cm above. The authors draw two directly operational conclusions: the linea alba is widest 2 cm above the umbilicus, during pregnancy as well as postnatally; and in primiparous women, the IRD can be considered “normal” at wider values than in nulliparous women ¹². This is a strong argument against using a single 2 cm threshold applied at every level and to every woman.

How sensitive the figure is to the chosen threshold can also be read in the long-term prevalence data: in 1 000 women assessed by ultrasound, prevalence was 36 %, 31 %, 22 %, 26 % and 30 % at 3, 5, 10, 20 and 30 years postnatally with the criterion IRD > 2 cm, but only 13 %, 8 %, 6 %, 8 % and 10 % with the criterion IRD > 3 cm ³. One centimetre of threshold divides prevalence by three: any reading of the literature requires checking the definition used.

Postnatal epidemiology: very common, largely self-resolving, never quite resolved

Strong evidence The most cited figure in this field comes from Sperstad's prospective cohort of 300 primiparous women, with diastasis defined by palpation (≥ 2 fingerbreadths): prevalence was 33,1 % at 21 weeks of pregnancy, 60,0 % at 6 weeks postnatally, 45,4 % at 6 months and 32,6 % at 12 months postnatally ¹. Two readings coexist in these four figures, and both are true: spontaneous resolution is substantial (from 60 % to 32,6 % in one year, with no intervention), and one woman in three is still affected a year after giving birth.

Mota's longitudinal ultrasound follow-up shows the same trajectory with an even more striking amplitude: in 84 primiparous women measured at week 35 of gestation then at 6–8, 12–14 and 24–26 weeks postnatally, the prevalence of diastasis falls from 100 % at the end of pregnancy to 39 % at 6 months postnatally ²⁴. Every woman has a diastasis at term (diastasis in pregnancy is the rule, not the exception) and four in ten still do at the sixth month, spontaneously.

The figures nevertheless vary widely with the population and the method. A Chinese observational study of 534 women, with diastasis measured by palpation, reported a prevalence of 78,1 % (417/534) ¹³. The message is not that one figure is wrong: it is that prevalence only means something when it comes with its definition, its postnatal time point and its measurement method.

And in the very long term?

Moderate evidence Diastasis does not disappear: it stabilises, then rises again. In the cross-sectional ultrasound study of 1 000 women assessed at 3, 5, 10, 20 and 30 years postnatally, prevalence (IRD > 2 cm) was 36 %, 31 %, 22 %, 26 % and 30 % ; with the criterion IRD > 3 cm, 13 %, 8 %, 6 %, 8 % and 10 % ³. The decline stops at around 10 years postnatally, then prevalence rises again, and about one woman in ten still has a diastasis > 3 cm thirty years after giving birth.

Risk factors: what holds up, and what does not

Not all the “obvious” risk factors survive analysis. In 84 primiparous women followed by ultrasound, no statistically significant difference was found at 6 months postnatally in pre-pregnancy BMI, gestational weight gain, the baby's birth weight or abdominal circumference between women with and without diastasis ²⁴In another cohort, each additional year of maternal age increased the risk by 10 % (OR 1,10; 95 % CI 1,04–1,16; p = 0,002) and the number of births doubled it (OR 2,09; 95 % CI 1,30–3,37; p = 0,002), but fetal weight, pre-pregnancy BMI and postnatal BMI were not significant factors in the final model (p > 0,05) ¹⁴.

The most honest summary remains that of Cavalli's review: among all the risk factors proposed, only the number of pregnancies, BMI and diabetes emerge as the most plausible ¹⁶.

Anatomy: the linea alba is not a simple fibrous band

Understanding diastasis means understanding the structure that widens. The linea alba is an aponeurotic interweaving organised into two families of fibres with distinct mechanical roles : the transverse fibres resist intra-abdominal pressure, whereas the oblique fibres are mainly loaded during trunk movements ¹⁸. This architecture directly illuminates the respective roles of the transversus and the obliques: they are not interchangeable synergists: they tension the linea alba along different vectors.

Axer's morphological study also reports sex-related differences that are not incidental to the topic at hand: in women, the infra-umbilical linea alba is thinner but wider than in men, with a higher proportion of transverse fibres relative to oblique fibres. The mean diameter of the fibril bundles was also smaller in the supra-umbilical region than in the infra-umbilical region. The authors honestly state that whether these morphological differences reflect an adaptation to the biomechanical stress of pregnancy remains to be demonstrated ¹⁸.

The histological organisation of the collagen completes the picture: transverse fibres on the dorsal side, oblique fibres on the ventral side. Under tension, the oblique fibres of the ventral layer reorient towards the axis of traction, which progressively increases the stiffness of the tissue and produces a non-linear stress-strain relationship. Elastin, for its part, forms a superficial layer that covers the collagen network and follows its movements, which suggests that it provides its elastic recoil: the return to the original shape after deformation ¹⁹. Put simply for the patient: collagen takes the load, elastin brings the tissue back to its shape.

An anisotropic tissue: it does not deform the same way in every direction

Moderate evidence The linea alba is anisotropic. Under a physiological abdominal pressure of about 20 kPa, its Young's modulus is approximately 50 kPa in the transverse direction against about 20 kPa in the longitudinal direction, for strains of around 6 % in both axes, that is a compliance ratio of about 2:1 between longitudinal and transverse. The corresponding biaxial forces are 3,4 N/mm transversely and 1,5 N/mm longitudinally. The overall behaviour is non-linear elastic, typical of soft biological tissues ²⁰.

What this means in practice: the wall is roughly twice as stiff transversely as longitudinally. It is therefore structurally built to resist the transverse tension imposed by intra-abdominal pressure: exactly what pregnancy will load, right up to its functional breaking point.

Pathophysiology of the distension: mechanics and tissue quality

Distension in pregnancy is massive and quantifiable. In 84 primiparous women followed by ultrasound, at the end of pregnancy (weeks 35–41) the IRD ranged between the 20^th and 80^th percentiles at 49–79 mm at 2 cm below the umbilicus, 54–86 mm at 2 cm above, and 44–79 mm at 5 cm above ¹². In other words, the supra-umbilical IRD can exceed 8 cm at term, against less than 10 mm in nulliparous women ¹¹ : a factor of 8 to 9.

The spontaneous narrowing that follows is considerable (the same values fall back to 9–21 mm, 17–28 mm and 12–24 mm at 6 months postnatally ¹²), but it is early and incomplete. The clearest demonstration of this comes from Coldron's study, which followed 115 postnatal women by ultrasound against 69 age-matched nulliparous controls: the rectus abdominis is significantly thinner, wider, and the IRD significantly larger than in the controls at all measurement time points: day 1, 2 months, 6 months and 12 months (p < 0,0001 for the IRD at all four time points). Most of the recovery takes place over the first two months, the muscle thickens (p = 0,0003), width and IRD decrease (p < 0,0001 and p = 0,0002), but the values do not return to those of the controls at 12 months ²¹.

The same plateau is found for function. Liaw followed 40 postnatal women (measurements at 4–8 weeks then 6–8 months, ultrasound IRD at 4 sites around the umbilicus) compared with 20 matched nulliparous women: the IRD decreases significantly 2,5 cm above the umbilical ring (p = 0,013) and at its upper margin (p = 0,002), but neither the IRD nor abdominal muscle function had returned to normal values at 6 months ²². Spontaneous improvement does not mean cure.

It is not just stretching: the connective tissue is altered

Moderate evidence Reducing diastasis to passive mechanical distension would be a modelling error. In a case-control study of 18 women with diastasis and 18 without (midline fascia samples, immunohistochemistry), both type I and type III collagen were significantly less abundant in women with diastasis (p < 0,001). Supra-umbilically, type I collagen measured 244,5 ± 73,5 kpixels against 381,1 ± 101,1 in the controls; infra-umbilically, 217,1 ± 58,8 against 397,4 ± 82,9. Type III collagen had also collapsed (54,3 ± 33,1 vs 154,9 ± 59,4 supra-umbilically; 58,5 ± 36,9 vs 152,0 ± 68,0 infra-umbilically). The authors conclude that a low level of type I and III collagen in the midline could play a key role in the development of diastasis ²³.

This carries clinical weight: it suggests that part of the diastasis stems from a tissue quality on which exercise has no direct purchase, and it offers a plausible explanation for the absence of complete anatomical resolution described in the rehabilitation studies.

A reorganised wall, not merely a stretched one

Limited evidence Diastasis also alters the mechanical properties of the muscles themselves, and does so non-uniformly. On ShearWave elastography, in 36 postnatal women with diastasis against 24 healthy nulliparous women, shear wave velocity (a marker of stiffness) was significantly lower in the rectus abdominis (p = 0,003) and in the external oblique (1,65 ± 0,15 vs 1,79 ± 0,14; p = 0,001), but significantly higher in the transversus abdominis (p < 0,001). The maximum separation was located at the umbilicus (4,59 ± 1,14 cm) ²⁷.

This contrast (rectus abdominis and external oblique softened, transversus stiffened), suggests a reorganisation of the wall rather than simple passive stretching. The authors do, however, explicitly urge caution in interpreting the correlation between wave velocity and IRD in the rectus abdominis ²⁷ : the signal is interesting, the sample remains small and the mechanism is not established.

The biomechanical corollary: not every exercise pulls in the same direction

The anisotropy of the linea alba and the specialisation of its fibres translate directly into experimental observations. In 38 primiparous women, the IRD above the umbilicus was significantly reduced during the abdominal crunch, whereas the IRD below the umbilicus was significantly wider during the abdominal drawing-in exercise (drawing-in, transversus activation) than at rest ²⁴. The same exercise therefore does not produce the same effect at the two levels.

More importantly, visibly reducing the gap is not necessarily the functional objective. In women with diastasis, the automatic curl-up narrows the IRD but distorts the linea alba more, whereas pre-activation of the transversus reduces the IRD less while distorting the linea alba less. The authors stress that this smaller narrowing of the IRD by the transversus, advised against until now, could on the contrary favour abdominal mechanics through tension transfer ²⁵. This is the conceptual turning point of the whole subject: “closing the gap” is not synonymous with “transmitting forces well”.

What diastasis does, and does not, cause

Strong evidence Contrary to a stubborn belief in rehabilitation, the Norwegian prospective cohort found no link between diastasis and pelvic floor dysfunction : women with diastasis had neither a weaker pelvic floor, nor more urinary incontinence, nor more prolapse, at 6 weeks, 6 months and 12 months postnatally. Counter-intuitively, at 6 weeks postnatally prolapse was even significantly more frequent in women without diastasis (15,9 % vs 4,1 %; p = 0,001) ²⁶.

This result withstands the severity test. In a retrospective cohort of 229 women during the first year postnatally, no difference in urinary incontinence or prolapse was observed between women with and without diastasis, and this held whatever IRD threshold was used (20, 30, 40 or 50 mm) ²⁷. A wider diastasis does not come with a more symptomatic pelvic floor: a strong argument against the idea that “closing the gap” protects the pelvic floor.

Moderate evidence When an association is found, it is weak. In a prospective study of 150 women from 6 weeks to 6 months postnatally, the correlation between diastasis and stress urinary incontinence symptoms was only r = 0,283 ; those with maximum voluntary contraction of the pelvic floor (r = −0,278) and contraction duration (r = −0,274) were also weak, and no correlation was found with the area of the urogenital hiatus ²⁸.

The impact is better read elsewhere: in reported symptoms and abdominal strength. In primiparous women assessed postnatally, diastasis was not correlated with morphological changes of the pelvic floor on imaging, but was associated with a significantly higher PFDI-20 urinary symptom score (12,5 ± 22,8 without diastasis vs 26,8 ± 18,2 with; p = 0,01). And extensive diastases (grades 2–3) showed significantly reduced abdominal strength and endurance : dynamic endurance test 13,4 ± 11,8 vs 6,46 ± 4,59 repetitions (p = 0,025); manual muscle testing 4 vs 3 (p = 0,04) ²⁹.

Finally, quality of life emerges as a more relevant outcome measure than pelvic floor symptoms. In 253 patients followed after giving birth, severe diastasis had a significant impact on quality of life (HerQLes score) at birth (p = 0,001) and at 3–6 months (p = 0,01), but no effect on pelvic floor symptoms measured with the FPFQ ¹⁷. A mixed-methods study confirms a negative effect on quality of life, functional capacity and urogynaecological and digestive health, along with an emotional impact involving altered body image and poor perceived health: the authors describing feelings of abandonment by health institutions, shame, sadness, helplessness, a lack of self-esteem, resignation and social pressure ³⁰.

The scale of the aesthetic concern is, moreover, widely underestimated in clinic. In a cross-sectional study of 460 primiparous women at 6–8 months postnatally, 73,3 % reported having worried during pregnancy about the appearance of their abdomen after giving birth, the mean degree of concern about their current abdominal appearance was 5,5/10 (SD 2,4), and nearly 80 % felt their abdominal muscles were weaker than before pregnancy. Women reporting a midline protrusion (20,9 %) described themselves as weakened significantly more often than those without protrusion ³¹.

📏 How do you measure and diagnose a diastasis?

Diagnosing diastasis recti abdominis looks simple: you part the muscles, you measure, you compare with a threshold. In practice, each of these three steps is booby-trapped. The choice of tool changes inter-rater agreement, the measurement site changes reliability, and the chosen threshold changes prevalence to a considerable degree. In one and the same cross-sectional cohort of 1 000 women assessed by ultrasound, prevalence falls from 36 % to 13 % at 3 years postnatally depending on whether the criterion is an inter-recti distance (IRD) greater than 2 cm or greater than 3 cm ³. In other words: the figure you announce to your patient depends as much on your method as on her abdomen.

What exactly is measured: the inter-recti distance (IRD)

The reference variable is the inter-recti distance : the distance separating the medial borders of the two rectus abdominis muscles, that is, the width of the interposed linea alba. It is neither a measure of a “hole”, nor a measure of hernia, nor a measure of tone: it is a transverse distance, measured at a given point, in a given position, at a given moment of the contractile cycle.

This precision is not methodological pedantry. The linea alba is not a homogeneous tissue: its transverse fibres oppose intra-abdominal pressure while its oblique fibres are mainly loaded during trunk movements, and its structure differs by level, in women, the infra-umbilical portion is thinner but wider than in men, with a higher proportion of transverse fibres relative to oblique fibres ¹⁸. Mechanically, this tissue is anisotropic: under a physiological abdominal pressure of about 20 kPa, its Young's modulus is around 50 kPa in the transverse direction against about 20 kPa in the longitudinal direction, a compliance ratio of roughly 2:1 ²⁰. A structure that does not deform in the same way along different axes or at different levels cannot honestly be summed up by a single figure.

And diastasis does not come down to passive distension: in a case-control study of 18 women with diastasis and 18 without, both type I and type III collagen were significantly less abundant in the midline fascia samples of women with diastasis (p < 0,001): 244,5 ± 73,5 kpixels against 381,1 ± 101,1 for type I collagen supra-umbilically ²³. What you measure with a tape or an ultrasound probe is therefore the visible symptom of a qualitative alteration of the connective tissue, not merely a geometric gap.

Finger palpation: accessible, standardisable, but imperfect

The digital method remains the clinical entry point, and it is the one used by the landmark prospective cohort of 300 primiparous women: diastasis there was defined as a palpated separation of at least 2 fingerbreadths, assessed at three levels (4,5 cm above the umbilicus, at the umbilicus, and 4,5 cm below), with the patient supine performing an abdominal crunch ¹. It is with this protocol that the classic prevalence figures were established: 33,1 % at 21 weeks of pregnancy, 60,0 % at 6 weeks postnatally, 45,4 % at 6 months and 32,6 % at 12 months ¹.

Two immediate practical lessons. First, measurement is not taken at a single point : the protocol explicitly requires going above and below the umbilicus. Second, the test is done in contraction (crunch), not at rest, which is not neutral, as we shall see.

The limitation is documented. The systematic review of measurement methods (13 studies evaluating fingerbreadth, tape measure, callipers, ultrasound, CT and MRI) concludes that the fingerbreadth method offers only moderate inter-rater agreement: 63 %, weighted Kappa = 0,53 ⁶. Clinical translation: two physiotherapists assessing the same patient will agree about two times out of three. For longitudinal follow-up, “is it getting better?”, that is structurally insufficient, all the more so because fingerbreadth varies from one examiner to another and has no standardised metric value.

Ultrasound: the reference method, provided you know where to place the probe

The systematic review of measurement methods is unambiguous: “ultrasound and callipers are the adequate methods for assessing diastasis, with low measurement error above the umbilicus” ⁶. The reproducibility of 2D ultrasound is good to very good, with test-retest intraclass correlation coefficients between 0,74 and 0,90, and intra-observer reproducibility on the same images exceeding 0,90 ⁹.

But this quality is not uniform, and this is probably the most underestimated point of the whole subject. Reliability depends massively on the site. In Keshwani ⁷, at rest, the ICC reaches 0,91 at 5 cm above the umbilicus but falls to 0,72 at the upper edge of the umbilicus; on head lift, it goes from 0,96 at 5 cm above to 0,63 at the umbilical level. The same signal in Mota ⁹ : the only exception to good reliability is the measurement 2 cm below the umbilicus during the crunch, with an ICC collapsed to 0,50.

The practical recommendation that follows is explicit: favour standardised supra-umbilical measurement sites ⁷. If you have to follow a patient over time, always measure at the same place, above the umbilicus, in the same position, and write it down. An operational protocol documented in sports practice uses four ultrasound sites: xiphoid, supra-umbilical, umbilical and infra-umbilical ³³. The seminal palpation study uses three: 4,5 cm above, at, and 4,5 cm below ¹. The exact number matters less than consistency: your protocol, written down, reproduced identically.

Which threshold? The worst-posed question of the subject

Three families of reference points must be distinguished, and not confused.

1. Values in healthy nulliparous women. The meta-analysis of ultrasound reference values establishes that the maximum inter-recti distance reported in healthy nulliparous women is below 10 mm at every location, with pooled values of approximately 8,77 mm in the umbilical zone, 7,22 mm in the epigastric zone and 4,09 mm in the infra-umbilical zone ¹¹. This is the “ideal” anatomical reference point, and that is precisely why it should not serve as a therapeutic goal postnatally.

2. Normal values in primiparous women. They are not the same, and this has been demonstrated. In the longitudinal ultrasound follow-up of 84 primiparous women, at 6 months postnatally, the 20^th and 80^th percentiles corresponded to 9–21 mm at 2 cm below the umbilicus, 17–28 mm at 2 cm above and 12–24 mm at 5 cm above ¹². The authors explicitly conclude that “in primiparous women, the IRD can be considered normal up to wider values than in nulliparous women”, and that the linea alba is widest 2 cm above the umbilicus, during pregnancy as well as postnatally ¹². This is a head-on argument against using a single 2 cm threshold at every level.

3. The operational thresholds used in studies. They vary, and you need to know this to read the literature: ≥ 2 fingerbreadths on palpation ¹, IRD ≥ 16 mm at 2 cm below the umbilicus ², IRD ≥ 28 mm at rest and/or a visible protrusion as an inclusion criterion in pregnancy ³⁴, IRD ≥ 2,8 cm ³⁵, or else > 2 cm versus > 3 cm in epidemiology ³. A retrospective cohort of 229 women even tested 20, 30, 40 and 50 mm in turn as diagnostic thresholds ²⁷: a sign that the scientific community itself has no consensus value.

To put the scale of the pregnancy phenomenon in context: at the end of pregnancy (weeks 35–41), the 20^th and 80^th percentiles of the IRD ranged between 49–79 mm at 2 cm below the umbilicus, 54–86 mm at 2 cm above and 44–79 mm at 5 cm above ¹². At term, a supra-umbilical IRD greater than 8 cm falls within the normal range. Measuring an “enormous” diastasis at 38 weeks has no prognostic value in itself.

Position and instruction: you are not measuring the same thing depending on what you ask for

This is the methodological trap least well mastered in the clinic. The motor instruction given during the measurement changes the measured value, and not in the same direction at every level.

In 38 primiparous women, the IRD above the umbilicus was significantly reduced during the abdominal crunch, whereas the IRD below the umbilicus was significantly wider during the abdominal drawing-in exercise (drawing-in / transversus activation) than at rest ²⁴. The longitudinal study in 38 pregnant women with a diastasis ≥ 2,8 cm quantifies each instruction: pelvic floor contraction increases the IRD by 2 mm (95 % CI: 2 to 3), drawing-in by 4 mm (95 % CI: 3 to 5), the two combined by 5 mm (95 % CI: 4 to 6); conversely the head lift decreases it by 3 mm (95 % CI: -4 to -2), the curl-up by 3 mm (95 % CI: -4 to -2), the diagonal curl-up by 4 mm (95 % CI: -5 to -3) ³⁵.

In other words: depending on whether you say “pull your tummy in” or “lift your head”, you can shift the measurement by nearly a centimetre on the same patient, within the same minute. Any comparison between two assessments must therefore fix three parameters: the site, the position, the instruction.

And above all: the measured narrowing is not necessarily the objective. In women with diastasis, the automatic curl-up narrows the IRD but distorts the linea alba more, whereas pre-activation of the transversus reduces the IRD less while distorting the linea alba less; the authors stress that this smaller narrowing by the transversus, advised against until now, could on the contrary favour abdominal mechanics through tension transfer ²⁵. A “smaller gap” on the screen is not “better function”.

The functional assessment: what the ruler does not measure

This is where the physiotherapist adds value, because the literature is clear on one point: the width of the gap correlates poorly with what makes patients suffer.

Do not try to explain low back pain by the diastasis. In the prospective cohort of 300 primiparous women, the presence of a diastasis at 12 months postnatally was not associated with more lumbopelvic pain: no significant difference between women with and without diastasis (p = 0,10) ¹.

Nor should you present it as the cause of a pelvic floor disorder. The Norwegian cohort finds no significant difference in pelvic floor variables at 6 weeks, 6 months and 12 months postnatally, nor in the prevalence of urinary incontinence; at 6 weeks, prolapse was even significantly more frequent in women without diastasis (15,9 % vs 4,1 %, p = 0,001) ²⁶. This absence of a link withstands the severity test: in a retrospective cohort of 229 women, no difference in urinary incontinence or prolapse whatever the threshold used: 20, 30, 40 or 50 mm ²⁷. When an association is found, it is weak: r = 0,283 with stress urinary incontinence symptoms, r = -0,278 with maximum voluntary contraction of the pelvic floor, and no correlation with the area of the urogenital hiatus ²⁸.

Look instead at strength, endurance and lived experience. That is where the signal is. In primiparous women assessed postnatally, diastasis was not correlated with morphological changes of the pelvic floor on imaging, but extensive diastases (grades 2–3) showed significantly reduced abdominal strength and endurance: 13,4 ± 11,8 repetitions on the dynamic endurance test against 6,46 ± 4,59 (p = 0,025), and manual muscle testing of 4 against 3 (p = 0,04); the PFDI-20 urinary symptom score was also higher (12,5 ± 22,8 without diastasis vs 26,8 ± 18,2 with, p = 0,01) ²⁹. Your assessment must therefore include manual muscle testing of the abdominals and an endurance test, not just a ruler.

And ask about body image, every time. In a cross-sectional study of 460 primiparous women at 6–8 months postnatally, 73,3 % reported having worried during pregnancy about the appearance of their abdomen after giving birth, the mean degree of concern about their current abdominal appearance was 5,5/10 (SD 2,4), nearly 80 % felt their abdominal muscles were weaker than before pregnancy, and 20,9 % reported a midline protrusion: the latter describing themselves as weakened significantly more often than women without protrusion ³¹. Severe diastasis has a significant impact on quality of life measured with the HerQLes score, at birth (p = 0,001) and at 3–6 months (p = 0,01), with no effect on pelvic floor symptoms on the FPFQ ¹⁷. A mixed-methods study describes an emotional impact involving altered body image, feelings of abandonment by health institutions, shame, sadness, helplessness, lack of self-esteem, resignation and social pressure ³⁰. The complaint is almost never “3 cm”. It is “I do not recognise myself”.

What the assessment must screen for: hernia

This is the one part of the assessment where the issue is not nuance but safety. Hernia of the linea alba is a frequent comorbidity: in a multicentre retrospective study over 10 years covering 1 294 cases of diastasis, 35,8 % of the women had one or more hernias, umbilical hernia being the most prominent type; in women, age (OR 1,51 [1,33–1,72]; p = 0,000) and smoking (OR 1,66 [1,13–2,44]; p = 0,010) were risk factors for an associated hernia ⁴.

The stakes are surgical, and heavy. In 231 patients operated on for a small umbilical or epigastric hernia (< 2 cm) by simple suture without mesh, the recurrence rate was 31,2 % (29/93) in those with an associated diastasis, against 8,3 % (9/108) without diastasis (p < 0,001); the authors strongly recommend screening for diastasis preoperatively and using a prosthetic reinforcement when it is present ⁵. A painful or irreducible midline bulge calls for medical and surgical referral, with no delay for physiotherapy. In real-world practice the proportion is not negligible: in a pilot study of 37 sportswomen, 6 were referred for surgery: 2 for hernia, 4 for a diastasis greater than 4 cm ³³.

The chronological trap: spontaneous resolution contaminates your reading of the result

A diagnosis has a date. Without that date, it cannot be interpreted.

Spontaneous recovery is real but early and incomplete. In the ultrasound follow-up of 115 postnatal women compared with 69 age-matched nulliparous women, most of the recovery takes place over the first 2 months, the rectus abdominis thickens (p = 0,0003), its width and the IRD decrease (p < 0,0001 and p = 0,0002), but the values do not return to those of the controls at 12 months : at every measurement time point (day 1, 2 months, 6 months, 12 months), the rectus abdominis remains significantly thinner and wider, and the IRD significantly larger (p < 0,0001 for the IRD at all four time points) ²¹. The same signal in Liaw ²² : in 40 women followed from 4–8 weeks to 6–8 months, the IRD decreases significantly 2,5 cm above the umbilical ring (p = 0,013) and at its upper margin (p = 0,002), but normal values are not reached at 6 months. Prevalence, for its part, falls from 100 % at the end of pregnancy to 39 % at 6 months postnatally, with no intervention ².

A direct methodological consequence, and it applies to your own practice too: Skoura's scoping review ³⁶ stresses that most studies included women within the first 6 months postnatally, “a period during which the spontaneous reduction in inter-recti distance may be confounded with the effect of the intervention”. A “good result” from a protocol started at 6 weeks is therefore, in part, natural history. Do not take all the credit for it, and do not conclude too quickly that a woman seen late has failed.

In the long term, finally, the phenomenon does not disappear: prevalence declines until around 10 years postnatally then rises again (36 %, 31 %, 22 %, 26 % and 30 % at 3, 5, 10, 20 and 30 years with the > 2 cm criterion), and about one woman in ten still has a diastasis > 3 cm thirty years on ³.

A word on what you will find in front of you

Your patients often arrive with a diagnosis already made by social media, and a list of prohibitions. A mixed-methods study screened 1 000 Instagram posts on diastasis, of which 28 were included: 61 % (n = 17) offered recommendations that were not evidence-based and only 7,1 % (n = 2) cited a scientific source, quality being rated poor on the QUEST tool; the twenty women with diastasis who were interviewed reported confusion, misinformation and nocebo effects when faced with the ubiquitous prescriptive “do / do not” lists, while recommendations consistent with the literature influenced only 20 % of them positively ³⁷. The diagnostic appointment is therefore also, and sometimes first of all, an appointment for dismantling beliefs.

⚠️ What are the risk factors and the natural course?

Two questions dominate the first postnatal appointment: “why me?” and “will it close on its own?”. The literature answers both, but not in the expected way. The “obvious” risk factors (the baby's weight, weight gain) hold up poorly in multivariate models, while spontaneous recovery is at once substantial, early and incomplete. And the reflex link between diastasis and low back pain does not hold.

The risk factors that survive multivariate analysis

The first observation is that pregnancy itself is the risk factor, and that the number of pregnancies is the most robust determinant. A literature review dedicated to risk factors concludes that, among all the candidates proposed, only the number of pregnancies, BMI and diabetes emerge as the most plausible: the more pregnancies a woman has had, the greater the risk of diastasis Moderate evidence ¹⁶.

Recent cohorts quantify this dose effect. In a cohort of 4 426 women assessed at 6 weeks postnatally, multiparous women had a risk of diastasis more than twice as high as nulliparous women (OR 2,67; 95 % CI 1,30–5,45) ¹⁵. Another regression model finds the same order of magnitude: the number of births doubles the risk (OR 2,09; 95 % CI 1,30–3,37; p = 0,002), and each additional year of maternal age increases it by 10 % (OR 1,10; 95 % CI 1,04–1,16; p = 0,002) ¹⁴.

A caveat on age, though: Cavalli's review points out that the results are contradictory across cohorts, not significant in Mota and Sperstad, a risk factor in Spitznagle, but protective in Wu ¹⁶. Age is therefore not a reliable triage marker at the individual level.

Mode of birth: caesarean section, a risk factor to be qualified

This is one of the rare points where the data converge, in mirror image. In the cohort of 4 426 women, vaginal birth is associated with a reduced risk of diastasis (OR 0,45; 95 % CI 0,40–0,51), as is type I pelvic floor strength of grade II to IV: a direct argument in favour of pelvic floor work in postnatal rehabilitation ¹⁵. An observational study of 534 Chinese women (palpated diastasis, prevalence 78,1 %) confirms the symmetrical reading: caesarean section is an independent risk factor, with an incidence 2,297 times higher (OR 2,297; 95 % CI 1,327–3,978; p = 0,003) ¹³. In 253 patients followed after giving birth, caesarean section (p = 0,05) and multiparity (p = 0,04) also appeared as factors for persistence of the diastasis ¹⁷.

The qualification comes from Cavalli's review: caesarean section would appear to be a risk factor only in women who have given birth twice ¹⁶. The clinical message is therefore not “caesarean section causes diastasis”, but: mode of birth alters the risk, in interaction with parity.

The false risk factors: what the assessment must not over-interpret

This is probably the most counter-intuitive point of this section. In He's final model, fetal weight, pre-pregnancy BMI and postnatal BMI were not significant factors (p > 0,05) ¹⁴. And Fernandes da Mota's prospective ultrasound study of 84 primiparous women points the same way: at 6 months postnatally, no statistically significant difference was found in pre-pregnancy BMI, gestational weight gain, the baby's birth weight or abdominal circumference between women with and without diastasis ².

This is not a definitive refutation: in the long term, a higher BMI is associated with diastasis. Lin's cross-sectional ultrasound study of 1 000 women assessed at 3, 5, 10, 20 and 30 years postnatally shows that the independent factors change with the postnatal time point : at 3 years, they are the number of deliveries and twin pregnancies (p = 0,000 and 0,001); at 10 years, BMI and the number of deliveries (p = 0,000); at 20 and 30 years, diabetes (p = 0,000 and 0,004) ³.

Gestational weight gain and the baby's weight, the two explanations patients most often give themselves, do not come out of the models at 6 months. What the assessment retains is parity, metabolic background and mode of birth.

The natural course: substantial resolution, but not cure

The landmark cohort is Norwegian: 300 primiparous women followed prospectively, diastasis measured by palpation (separation ≥ 2 fingerbreadths, tested at three levels, 4,5 cm above, at, and 4,5 cm below the umbilicus, with the patient supine performing an abdominal crunch). Prevalence was 33,1 % at the 21^st week of pregnancy, 60,0 % at 6 weeks postnatally, 45,4 % at 6 months and 32,6 % at 12 months ¹ High-quality evidence.

Fernandes da Mota's longitudinal ultrasound follow-up (84 primiparous women, measurements at week 35 of gestation then at 6–8, 12–14 and 24–26 weeks postnatally) gives a comparable slope, with more extreme figures owing to the method and the threshold: diastasis falls from 100 % of women at the end of pregnancy to 39 % at 6 months postnatally ². In other words: about 4 women in 10 still have a diastasis at the 6^th month, with no intervention at all.

The scale of the distension of pregnancy and of its retreat can be quantified. In these same 84 primiparous women, at the end of pregnancy (weeks 35–41), the 20^th–80^th percentiles of the inter-recti distance (IRD) were 49–79 mm at 2 cm below the umbilicus, 54–86 mm at 2 cm above and 44–79 mm at 5 cm above. At 6 months postnatally, these same values fall back respectively to 9–21 mm, 17–28 mm and 12–24 mm ¹². The linea alba can therefore exceed an 8 cm gap at term supra-umbilically, and retract by more than 60 mm in six months: spontaneously.

The plateau: why “it will keep closing” is a misuse of language

This is where reassurance has to become precise. Recovery is real, but early and incomplete.

Coldron's study (115 postnatal women followed by ultrasound against 69 age-matched nulliparous women, measurements at day 1, 2 months, 6 months and 12 months) is the clearest demonstration. Most of the recovery takes place over the first two months : the rectus abdominis thickens (p = 0,0003), its width and the IRD decrease (p < 0,0001 and p = 0,0002). But at every measurement time point, including 12 months, the rectus abdominis remains significantly thinner (p < 0,0001 from day 1 to 6 months; p < 0,0478 at 12 months) and wider (p < 0,0001 then p = 0,0326 at 12 months) than in the controls, and the IRD remains significantly larger at all four time points (p < 0,0001) ²¹.

Liaw finds exactly this plateau for function as well as for anatomy: in 40 women followed from 4–8 weeks to 6–8 months (ultrasound IRD at 4 sites around the umbilicus) compared with 20 matched nulliparous women, the IRD decreases significantly 2,5 cm above the umbilical ring (p = 0,013) and at its upper margin (p = 0,002), but normal values are not reached at 6 months: neither for the IRD nor for abdominal muscle function ²².

“Spontaneous improvement does not mean cure.” Recovery plateaus at around 6 to 12 months, and the postnatal anatomy does not become nulliparous again.

This conclusion has a major normative corollary: in primiparous women, the IRD can be considered “normal” at wider values than in nulliparous women ¹², whereas the meta-analysis of reference values in healthy nulliparous women places the maximum IRD below 10 mm at every location (about 8,77 mm in the umbilical zone, 7,22 mm in the epigastric zone, 4,09 mm in the infra-umbilical zone) ¹¹. Comparing a woman 6 months after her first birth with the nulliparous norm is manufacturing a pathology.

And after 12 months? Diastasis stabilises, then rises again

The natural history does not stop at the first year. Lin's cross-sectional ultrasound study of 1 000 women shows that the decline stops at around 10 years postnatally, then prevalence rises again :

About one woman in ten keeps a diastasis > 3 cm thirty years later ³. The nadir is at 10 years, then the effect of age takes over again. Diastasis is therefore not an episode that closes: it is a trajectory that plateaus, then reopens.

Diastasis and lumbopelvic pain: the link that does not exist

This is one of the most important, and most poorly transmitted, messages of this literature. In the prospective cohort of 300 primiparous women, at 12 months postnatally there was no difference in reported lumbopelvic pain between women with and without diastasis (p = 0,10) ¹ High-quality evidence.

The same group tested the neighbouring hypothesis, diastasis = weakened pelvic floor, and refuted it as well: no significant difference in pelvic floor variables at 6 weeks, 6 months and 12 months postnatally, no excess of urinary incontinence, no excess of prolapse. Frankly counter-intuitive: at 6 weeks, prolapse was even significantly more frequent in women WITHOUT diastasis (15,9 % vs 4,1 %; p = 0,001) ²⁶.

The absence of a link withstands the severity test. In a retrospective cohort of 229 women during the first year postnatally, no difference in urinary incontinence or prolapse was observed between women with and without diastasis, whatever IRD threshold was used (20, 30, 40 or 50 mm) ²⁷. A wider diastasis does not come with a more symptomatic pelvic floor, which destroys the argument that “closing the gap” protects the pelvic floor.

When an association is found, it is weak. In a prospective study of 150 women from 6 weeks to 6 months postnatally, the correlation between diastasis and stress urinary incontinence symptoms was only r = 0,283, and those with maximum voluntary contraction of the pelvic floor (r = −0,278) and with contraction duration (r = −0,274) were also weak; no correlation with the area of the urogenital hiatus ²⁸.

So where is the real impact to be read?

Not in low back pain, not in pelvic floor anatomy, but in abdominal strength, in reported symptoms and quality of life.

• Strength and endurance. In primiparous women assessed postnatally, diastasis was not correlated with morphological changes of the pelvic floor (imaging), but extensive diastases (grades 2–3) showed significantly reduced abdominal strength and endurance: dynamic endurance test 13,4 ± 11,8 vs 6,46 ± 4,59 repetitions (p = 0,025); manual muscle testing 4 vs 3 (p = 0,04). The PFDI-20 urinary symptom score was, by contrast, higher in the diastasis group (12,5 ± 22,8 without vs 26,8 ± 18,2 with; p = 0,01) ²⁹.
• Quality of life. In 253 patients followed after giving birth, severe diastasis had a significant impact on quality of life (HerQLes score) at birth (p = 0,001) and at 3–6 months (p = 0,01), but no effect on pelvic floor symptoms measured with the FPFQ ¹⁷.
• Body image. In a cross-sectional study of 460 primiparous women at 6–8 months postnatally, 73,3 % reported having worried during pregnancy about the appearance of their abdomen after giving birth; the mean degree of concern about their current abdominal appearance was 5,5/10 (SD 2,4); nearly 80 % felt their abdominal muscles were weaker than before pregnancy; and the 20,9 % reporting a midline protrusion described themselves as weakened significantly more often than those without protrusion ³¹.
• Lived experience. A mixed-methods study reports a negative effect on quality of life, functional capacity and urogynaecological and digestive health, along with an emotional impact: altered body image, poor perceived health, feelings of abandonment by health institutions, shame, sadness, helplessness, lack of self-esteem, resignation and social pressure ³⁰.

The methodological trap: natural history contaminates the trials

Understanding the natural course is not only a matter of prognosis: it is the key to reading the whole rehabilitation literature. Skoura's scoping review (28 studies) stresses that most studies included women within the first 6 months postnatally, a period during which the spontaneous reduction in IRD may be confounded with the effect of the intervention ³⁶. A “good result” displayed by a protocol started at 6 weeks is therefore, to an unknown extent, natural history.

This bias also throws light on a result often cited the other way round: the meta-analysis of 9 RCTs (450 participants) shows that interventions started before 3 months postnatally achieve a greater reduction in IRD (MD −10,2 mm; 95 % CI −14,94 to −5,46) than late starts, which is exactly the window in which spontaneous resolution is strongest ³⁸.

A word on measurement, since it determines all these figures

The prevalence figures above are not interchangeable, because the methods are not. The systematic review of measurement methods (13 studies: fingerbreadth, tape measure, callipers, ultrasound, CT, MRI) retains ultrasound and callipers as the adequate methods, with low measurement error above the umbilicus; the fingerbreadth method offers only moderate inter-rater agreement (63 %; weighted Kappa = 0,53) ⁶.

Above all, reliability depends on the site. At rest, the ultrasound ICC reaches 0,91 at 5 cm above the umbilicus but falls to 0,72 at the upper edge of the umbilicus; on head lift, it goes from 0,96 (5 cm above) to 0,63 at the umbilical level ⁷. Practical recommendation: favour standardised supra-umbilical measurement sites. 2D ultrasound otherwise remains reliable on test-retest (ICC 0,74–0,90), with the notable exception of the measurement 2 cm below the umbilicus during the crunch (ICC 0,50); intra-observer reproducibility on the same images exceeds 0,90 ⁹.

💪 What rehabilitation for diastasis?

This is where the gap between everyday practice and the data is widest. Rehabilitation for diastasis was built around an implicit objective, close the gap, and an equally implicit prohibition, never do a crunch. Both deserve re-examination. Not in order to conclude that “physiotherapy is useless”, but to redeploy the intervention onto what it really changes: strength, function, lived experience, body image, and to identify the subgroup that belongs to another therapeutic tier.

The frame of reference is set by a systematic review of 20 articles (1 691 patients, 100 of them in physiotherapy): no physiotherapy programme has shown complete resolution of diastasis measured at rest ; physiotherapy achieves a limited reduction in inter-recti distance (IRD) during muscle contraction, whose impact on satisfaction, appearance and function remains uncertain ³⁹. This is not a failure: it is a redefinition of the target.

What rehabilitation changes, and what it does not

Three levels of evidence, three messages that do not say quite the same thing. They must be held together.

Low-quality evidence The seminal review on exercise and diastasis (8 studies, 336 women) concludes that non-specific exercise “may or may not” help prevent or reduce diastasis in the peri- and postnatal periods, because of the poor methodological quality of the included studies. A favourable signal exists antenatally, a 35 % reduction in the presence of diastasis (RR 0,65; 95 % CI 0,46–0,92), but it is to be interpreted with caution ⁴⁰.

Moderate evidence Nine years later, the update with meta-analysis (16 trials, 698 women) is sharper: conservative interventions do not produce a clinically significant reduction in IRD in postnatal women, but abdominal exercises “may provide other physical and psychosocial benefits” in the management of diastasis ⁴¹. The sentence deserves to be read twice: the benefit exists, it simply is not where it was being looked for.

Moderate evidence The most recent meta-analysis (9 RCTs, 450 participants) qualifies this further: structured exercise programmes significantly reduce the IRD, by −8,05 mm (95 % CI: −10,43 to −5,68; p < 0,05). But the same work immediately delivers the counterpoint: on function (Oswestry Disability Index, 3 comparisons from 2 RCTs, n = 115), no difference between groups (MD: 0,82; 95 % CI: −2,75 to 4,38; p = 0,75; I² = 0 %). The anatomical gain does not translate into superior functional recovery ³⁸.

Low-quality evidence (GRADE) Finally, the systematic review in the British Journal of Sports Medicine (eight databases searched up to 12 January 2024) concludes that “low” certainty of evidence supports a greater reduction in IRD, measured at rest and during a head lift, after abdominal muscle training compared with no exercise ⁴². In other words: resuming abdominal work is supported by the data, but with low certainty, which argues for individualised prescription rather than rigid protocols.

Why the gap does not close: what the tissue imposes

This anatomical limit is not a protocol flaw, it is written into the tissue. Diastasis does not come down to passive mechanical distension: it comes with a qualitative alteration of the connective tissue. In a case-control study (18 women with diastasis, 18 without, midline fascia samples, immunohistochemistry), type I collagen and type III collagen are both significantly less abundant in women with diastasis (p < 0,001): supra-umbilically, type I collagen at 244,5 ± 73,5 kpixels against 381,1 ± 101,1 in the controls; type III collagen at 54,3 ± 33,1 against 154,9 ± 59,4. The authors conclude that a low level of type I and III collagen in the midline could play a key role in the development of diastasis ²³. You cannot re-tighten a collagen-depleted tissue with exercises.

The wall itself reorganises, and not uniformly. On ShearWave elastography (36 postnatal women with diastasis vs 24 healthy nulliparous women), shear wave velocity, a marker of stiffness, is significantly lower in the rectus abdominis (p = 0,003) and in the external oblique (1,65 ± 0,15 vs 1,79 ± 0,14; p = 0,001), but significantly higher in the transversus (p < 0,001). The maximum separation was located at the umbilicus (4,59 ± 1,14 cm). This contrast (recti and external oblique softened, transversus stiffened), suggests a reorganisation of the wall, not simple passive stretching ²⁷. The authors nevertheless urge caution in interpreting the correlation between wave velocity and IRD in the rectus abdominis.

Finally, the linea alba is an anisotropic tissue: under a physiological abdominal pressure of about 20 kPa, its Young's modulus is around 50 kPa in the transverse direction against about 20 kPa longitudinally, for strains of around 6 % in both axes: a compliance ratio of roughly 2:1 between longitudinal and transverse (biaxial forces: 3,4 N/mm transversely, 1,5 N/mm longitudinally). The behaviour is non-linear elastic, typical of soft tissues ²⁰. Histologically, the collagen is organised in two layers (transverse fibres on the dorsal side, oblique fibres on the ventral side) and under tension, the ventral oblique fibres reorient towards the axis of traction, which progressively increases stiffness and produces the non-linear stress-strain relationship; the elastin fibres form a superficial layer that follows the movement of the collagen network, suggesting that they provide its elastic recoil ¹⁹. Collagen takes the load, elastin brings the tissue back to its shape.

Transversus and obliques: two vectors, not two interchangeable synergists

“Transversus work” is the historical foundation of rehabilitation for diastasis. Functional anatomy gives this intuition a real basis, but not the one usually assumed. The two families of fibres in the linea alba have distinct mechanical roles: the transverse fibres resist intra-abdominal pressure, whereas the oblique fibres are mainly loaded during trunk movements. The authors also note sex-related differences: in women, the infra-umbilical linea alba is thinner but wider than in men, with a higher proportion of transverse fibres relative to oblique fibres ¹⁸. Clinical translation: transversus and obliques are not interchangeable synergists, they tension the linea alba along different vectors.

But, and this is the awkward part, contraction of the transversus does not have the effect of closing the gap. In 38 primiparous women assessed by ultrasound, the IRD below the umbilicus was significantly wider during the abdominal drawing-in exercise (drawing-in, transversus activation) than at rest, whereas the IRD above the umbilicus was significantly reduced during the abdominal crunch exercise ²⁴. The result is reproduced in pregnant women: in an experimental longitudinal study in 38 women with a diastasis ≥ 2,8 cm (ultrasound at weeks 27 and 37), pelvic floor contraction increased the IRD by 2 mm (95 % CI: 2 to 3), drawing-in by 4 mm (95 % CI: 3 to 5) and the two combined by 5 mm (95 % CI: 4 to 6); conversely the head lift decreased it by 3 mm (95 % CI: −4 to −2), the curl-up by 3 mm (95 % CI: −4 to −2) and the diagonal curl-up by 4 mm (95 % CI: −5 to −3). The distance also increased naturally by 8 mm on average (95 % CI: 6 to 9) between weeks 27 and 37 ³⁵.

If narrowing of the IRD were taken as the quality criterion for an exercise, we would therefore have to ban the transversus and prescribe the crunch. That is exactly the opposite of the dominant discourse, and it is precisely what shows that narrowing of the IRD is a poor criterion.

The crunch controversy: what the gap does not tell you

Lee and Hodges' work reframes the question. In women with diastasis, the automatic curl-up narrows the IRD but distorts the linea alba more, whereas pre-activation of the transversus reduces the IRD less while distorting the linea alba less. The authors explicitly stress that this smaller narrowing of the IRD by the transversus, advised against until then for that very reason, could on the contrary favour abdominal mechanics through tension transfer ²⁵. A narrower gap with a linea alba that buckles is not a better result than a wider gap with a linea alba under tension.

High-quality evidence That leaves the practical question: does the crunch make diastasis worse? A methodologically high-quality randomised controlled trial (PEDro score 8/10) tested a 12-week home programme containing head lifts (curl-ups) in women with diastasis 6–12 months postnatally. Result: the programme neither worsened nor improved the IRD (mean difference 1 mm at rest 2 cm above the umbilicus; 95 % CI: −1 to 4), did not change the severity of pelvic floor disorders or low back or pelvic girdle pain, while increasing the strength and thickness of the abdominal muscles ³². The classic contraindication to the crunch in moderate diastasis is therefore not supported by this trial.

Consequence for measurement: if you assess the IRD, the exercise performed during the measurement determines the figure. Remember that ultrasound reliability is excellent above the umbilicus and poor at the umbilical level itself (ICC 0,91 at 5 cm above the umbilicus against 0,72 at the upper edge of the umbilicus at rest, and 0,96 against 0,63 on head lift ⁷), which argues for standardised supra-umbilical measurement sites. In 2D, test-retest reproducibility is good to very good (ICC 0,74 to 0,90), with the sole exception of the measurement 2 cm below the umbilicus during the crunch (ICC 0,50); intra-observer reproducibility on the same images exceeds 0,90 ⁹. And overall, ultrasound and callipers are the adequate methods, finger palpation offering only moderate inter-rater agreement (63 %; weighted Kappa = 0,53) ⁶.

Timing: start early, and the natural-history trap

The 2026 meta-analysis provides the most operational argument on timing: interventions started before 3 months postnatally achieve a greater reduction in IRD (MD: −10,2 mm; 95 % CI: −14,94 to −5,46) than late starts, and no significant difference appears between types of training (p = 0,32): it is the structure of the programme, not its recipe, that makes the difference compared with no intervention or standard care ³⁸. A reduction of nearly 1 cm is not trivial: it can tip a “moderate” diastasis into a “mild” one.

But this early timing is also the main interpretation bias of the whole literature. Skoura's scoping review (28 studies) stresses that most studies included women within the first 6 months postnatally, a period during which the spontaneous reduction in IRD may be confounded with the effect of the intervention ³⁶. And this spontaneous resolution is substantial. In 84 primiparous women followed by ultrasound, the IRD (20^th–80^th percentiles) goes from 49–79 mm at 2 cm below the umbilicus, 54–86 mm at 2 cm above and 44–79 mm at 5 cm above at the end of pregnancy (weeks 35–41), to 9–21 mm, 17–28 mm and 12–24 mm respectively at 6 months postnatally ¹². Prevalence, in this same cohort, falls from 100 % at the end of pregnancy to 39 % at 6 months postnatally, with no intervention ². And on palpation, in 300 primiparous women: 33,1 % at 21 weeks of pregnancy, 60,0 % at 6 weeks postnatally, 45,4 % at 6 months, 32,6 % at 12 months ¹.

A “good result” from a protocol started at 6 weeks is therefore, in part, natural history. This does not disqualify early rehabilitation: it requires you not to take all the credit for it in front of the patient.

Symmetrically, this spontaneous recovery plateaus and remains incomplete. In 115 postnatal women followed by ultrasound against 69 age-matched nulliparous women, the rectus abdominis remains significantly thinner and wider, and the IRD significantly larger than in the controls at every time point (p < 0,0001 for the IRD at day 1, 2, 6 and 12 months); most of the recovery takes place over the first 2 months (the muscle thickens, p = 0,0003; width and IRD decrease, p < 0,0001 and p = 0,0002), without a return to the control values at 12 months ²¹. Liaw finds the same trajectory in 40 women: the IRD decreases significantly 2,5 cm above the umbilical ring (p = 0,013) and at its upper margin (p = 0,002), but neither the IRD nor abdominal muscle function reaches normal values at 6 months ²². Spontaneous improvement does not mean cure, and at 30 years postnatally, about one woman in ten still keeps a diastasis > 3 cm, the decline stopping at around 10 years before rising again ³.

During pregnancy: neither a clear preventive benefit, nor a risk of worsening

High-quality evidence A randomised trial published in the Journal of Physiotherapy included 96 pregnant women (≥ 18 years, 24 weeks of gestation, IRD ≥ 28 mm at rest and/or visible protrusion), allocated to a 12-week programme of abdominal and pelvic floor exercises, or to a control group with no intervention. The effect of the intervention was 2 mm (95 % CI: −2 to 7) immediately after the programme: negligible, both at the end of the intervention and at 6 weeks postnatally ³⁴. The title of the article says the essential: pregnant women can train the abdominals and the pelvic floor without increasing diastasis.

This neutral result sits alongside Benjamin's antenatal signal, a 35 % reduction in the presence of diastasis (RR 0,65; 95 % CI 0,46–0,92), whose scope the authors themselves temper, concluding that non-specific exercise “may or may not” help ⁴⁰. Message for the antenatal appointment: prevention is not promised, but nothing is restricted either.

The pelvic floor impact: an overestimated association

This is probably the most counter-intuitive point of the whole file, and the one that should most change what is said to patients.

Moderate evidence In Bø's Norwegian prospective cohort, women with diastasis had neither a weaker pelvic floor, nor more urinary incontinence, nor more prolapse, at 6 weeks, 6 months and 12 months postnatally, no statistically significant difference on any pelvic floor variable. Counter-intuitively, at 6 weeks postnatally prolapse was even significantly more frequent in women without diastasis (15,9 % vs 4,1 %; p = 0,001) ²⁶.

The absence of an association withstands the severity test: in 229 women followed during the first year postnatally, no difference in urinary incontinence or prolapse between women with and without diastasis, whatever IRD threshold was used (20, 30, 40 or 50 mm) ²⁷. A wider diastasis does not come with a more symptomatic pelvic floor: a head-on argument against the idea that “closing the gap” protects the pelvic floor. And when an association is found, it is weak: in 150 women from 6 weeks to 6 months postnatally, the correlation between diastasis and stress urinary incontinence symptoms was only r = 0,283, that with maximum voluntary contraction of the pelvic floor r = −0,278 and that with contraction duration r = −0,274; no correlation with the area of the urogenital hiatus ²⁸.

A useful qualification: the impact is better read in reported symptoms than in pelvic floor anatomy. In primiparous women, diastasis was not correlated with morphological changes of the pelvic floor on imaging, but was associated with a significantly higher PFDI-20 urinary symptom score (12,5 ± 22,8 without diastasis vs 26,8 ± 18,2 with; p = 0,01); extensive diastases (grades 2–3) showed significantly reduced abdominal strength and endurance: dynamic endurance test: 13,4 ± 11,8 vs 6,46 ± 4,59 repetitions (p = 0,025); manual muscle testing: 4 vs 3 (p = 0,04) ²⁹. And in a cohort of 253 patients, severe diastasis had a significant impact on quality of life (HerQLes score) at birth (p = 0,001) and at 3–6 months (p = 0,01), but no effect on pelvic floor symptoms measured with the FPFQ ¹⁷.

Does that mean pelvic floor work should be abandoned? No, but for other reasons. In a cohort of 4 426 women at 6 weeks postnatally, type I pelvic floor strength of grade II to IV was associated with a reduced risk of diastasis, as was vaginal birth (OR 0,45; 95 % CI 0,40–0,51) ¹⁵. The pelvic floor appears here as a protective factor against diastasis: the argument runs in the opposite direction to the one usually invoked. Conversely, pelvic floor contraction increases the IRD acutely (+2 mm; 95 % CI: 2 to 3), and more still when combined with drawing-in (+5 mm; 95 % CI: 4 to 6) ³⁵: a further demonstration that the instantaneous IRD is not an indicator of effectiveness.

Finally, a point of vigilance that has nothing to do with the pelvic floor: low back pain. In the cohort of 300 primiparous women, the presence of a diastasis at 12 months postnatally was not associated with more lumbopelvic pain (p = 0,10) ¹. Diastasis should not be presented straight away as the cause of postnatal low back pain.

Sport, impact and return to activity

Diastasis resolves whatever the level of activity resumed: including high impact. In a longitudinal prospective cohort of 504 women followed at 3, 6, 9 and 12 months postnatally, grouped by their activity at 3 months into non-exercisers (n = 105), minimal low impact (n = 249), regular low impact (n = 117) and high impact (n = 32), with diastasis measured using callipers: the sensation of vaginal heaviness and the diastasis decreased in every group. Non-exercisers, by contrast, reported more severe pelvic girdle pain and had a weaker pelvic floor; stress urinary incontinence increased in them while it remained stable or improved in the active groups ¹⁰. The authors recommend encouraging a return to low-impact activity early after pregnancy.

In sportswomen, a dedicated protocol is feasible and compatible with an early return. A prospective observational pilot study in 37 sportswomen (training ≥ 3 times/week with competitions), IRD measured by ultrasound at 4 sites (xiphoid, supra-umbilical, umbilical, infra-umbilical) at inclusion (≈ 3 months postnatally), at 2 months and at 4 months, with 3 weekly sessions (1 supervised + 2 at home): the patients who followed the protocol improved on all 4 measurements and returned to sport early ³³. Above all, this work provides an observed triage algorithm : 31 patients benefited from conservative care, 6 were referred for surgery, 2 for hernia, 4 for a diastasis > 4 cm.

A contextual marker: in elite athletes, real-world practice runs well ahead of the classic reference points. In a comparative study including 34 Norwegian elite athletes (mean age 33,1 years) and 34 active controls (31,5 years), the majority of the athletes and one control in three returned to sport or exercise between 0 and 6 weeks postnatally ; four athletes had stress fractures postnatally, and the athletes described themselves as dissatisfied with the advice received on strength training and nutrition during pregnancy ⁴⁴. Caution: small sample, limited generalisability, and this study did not measure diastasis: it documents the gap between practice and support, not an effect on the linea alba.

Lists of “forbidden” exercises: an iatrogenic problem

The physiotherapist often inherits a patient who is already informed: badly. A mixed-methods study screened 1 000 Instagram posts on diastasis, of which 28 were included: 61 % (n = 17) offered recommendations that were not evidence-based and only 7,1 % (n = 2) cited a scientific source, quality being rated poor on the QUEST tool. Twenty women with diastasis were interviewed: the prescriptive “do / do not” lists were ubiquitous and the women reported confusion, misinformation and nocebo effects, while recommendations consistent with the literature influenced only 20 % of them positively (n = 4). The authors conclude that Instagram carries significant risks of misinformation regarding diastasis and participation in exercise ³⁷.

This informational context is not clinically neutral, because the psychological burden of diastasis is already high. In 460 primiparous women at 6–8 months postnatally, 73,3 % reported having worried during pregnancy about the appearance of their abdomen after giving birth, and the mean degree of concern about their current abdominal appearance was 5,5/10 (SD 2,4), with nearly 80 % feeling their abdominal muscles were weaker than before pregnancy; women reporting a midline protrusion (20,9 %) described themselves as weakened significantly more often than those without protrusion ³¹. A mixed-methods study also reports a negative effect of diastasis on quality of life, functional capacity and urogynaecological and digestive health, along with an emotional impact involving altered body image and poor perceived health, with feelings of abandonment by health institutions, shame, sadness, helplessness, a lack of self-esteem, resignation and social pressure ³⁰. These dimensions belong to the physiotherapy interview just as much as the analytical assessment does.

When to refer on: surgical indications and triage criteria

Physiotherapy is the first therapeutic tier for symptomatic diastasis ; surgery comes only second-line. The proposed sequence is explicit: when a patient has a symptomatic diastasis with no associated ventral hernia, the first option is physiotherapy; if she comes back after 2 to 6 months of conservative treatment with persistent symptoms, referral to a surgeon may be considered ; and where possible, surgery should wait until at least 1 year postnatally, since some patients experience spontaneous resolution during the first year ⁴³. The authors note in passing that evidence is lacking on which physiotherapy regimen to use and that success rates are not established.

The red flag that cannot wait: hernia

Hernia of the linea alba is a frequent comorbidity of diastasis, to be screened for systematically. In a multicentre retrospective series over 10 years covering 1 294 cases of diastasis, 35,8 % of the women and 56,1 % of the men had one or more hernias (p < 0,001), umbilical hernia being the most prominent type; in women, age (OR 1,51 [1,33–1,72]; p = 0,000) and smoking (OR 1,66 [1,13–2,44]; p = 0,010) were risk factors for an associated hernia ⁴.

The stakes are surgical and they are major. In 231 patients operated on for a small umbilical or epigastric hernia (< 2 cm) by simple suture without mesh, the recurrence rate was 31,2 % (29/93) in those with an associated diastasis, against 8,3 % (9/108) without diastasis (p < 0,001); the authors strongly recommend screening for diastasis preoperatively and using a prosthetic reinforcement when it is present (absorbable sutures did worse still: 28,9 % vs 10,8 %; p = 0,001) ⁵. A painful or irreducible midline bulge calls for medical and surgical referral, with no delay for physiotherapy.

The profile of the “training-resistant diastasis”

The only randomised trial comparing surgery with muscle training sheds precise light on the referral criterion. 86 patients: 29 retromuscular mesh, 27 double-row plication (Quill), 32 on a 3-month training programme. At 1 year, a significant muscle gain was achieved in every group, including the training group, but the perceived strength gain (VAS) was significantly greater in the two operated groups, and the patients in the training group continued to have bodily pain at follow-up ⁴⁵. Physiotherapy therefore genuinely strengthens the wall; it is the persistence of pain and discomfort despite that strengthening which marks out the candidate subgroup.

This subgroup has been described in its own right. A cohort of 60 postnatal women with diastasis and abdominal canister dysfunctions resistant to training underwent plication of the linea alba: at 3 years, every parameter of the Disability Rating Index was improved (p < 0,001), with gains in canister strength and stability (p < 0,001), in back muscle strength (p < 0,001) and in abdominal strength (p = 0,002); urinary incontinence (UDI-6, p < 0,001; IIQ-7, p = 0,004) and quality of life (SF-36) were also improved, stably between 1 and 3 years ⁴⁶. This is the best available argument for not letting a patient who is not responding drift.

What must be said honestly

Three pieces of information must be conveyed without embellishment.

First, there is no surgical consensus on the indications. A PRISMA systematic review (37 studies, 45 techniques) explicitly notes the lack of consensus on repair indications and on the optimal technique. After adjustment for concomitant hernia repair, no significant difference in complications (p = 0,165) or recurrences (p = 0,133) between open and laparoscopic approaches; double-layer suture closure is associated with a significantly lower complication rate (p = 0,002), and suture absorbability affects neither complications nor recurrences ⁴⁷.

Second, the outcome and risk figures. In 931 patients operated on for diastasis (18–70 years, follow-up from 3 weeks to 20 years): recurrence in 5 % of patients; the most frequent complication is seroma (7 %), then abdominal hypoaesthesia (6 %) and surgical site infection (2 %); chronic pain in 4 %. Satisfaction, assessed subjectively in the majority, is high overall, but this review does not allow simple plication and mesh reinforcement to be ranked ⁴⁸.

Third, a qualification about plication performed during an abdominoplasty: the functional benefit is more consistent than the strength gain. Systematic review of 7 articles (497 patients, mean age 44,5 years, 94,4 % women): improvement in the SF-36 physical function subscale in the 4 studies that used it, but only 2 of the 3 studies measuring abdominal strength show a significant improvement; overall complication rate of 17,0 % ⁴⁹.

Summary of clinical triage

In practice, the reasoning shifts: the success of rehabilitation is no longer judged by the width of a gap. It is judged by abdominal strength and endurance (significantly compromised in extensive diastases ²⁹, and improvable including with curl-ups ³²), by quality of life (an outcome on which severe diastasis genuinely weighs, unlike pelvic floor symptoms ¹⁷), by body image ³¹³⁰, and by the return to activity ¹⁰³³. And when strength returns without the pain giving way, you do not dig in: you refer ⁴⁵⁴⁶.

🔄 Recovery and return to activity

This is the part of care where most is expected of the physiotherapist, and the one where they are most at risk of taking credit for natural history. Diastasis recti abdominis largely closes on its own, very fast, then stops. Understanding when the spontaneous window opens and closes, what exercise really adds on top of it, and on what criteria to refer on, is the core of postnatal clinical reasoning.

The timeline: a substantial, early trajectory, then a plateau

Strong evidence The epidemiological reference remains the Norwegian prospective cohort of 300 primiparous women followed by palpation: the prevalence of diastasis (palpated separation ≥ 2 fingerbreadths) was 33,1 % at the 21^st week of pregnancy, 60,0 % at 6 weeks postnatally, 45,4 % at 6 months and 32,6 % at 12 months postnatally ¹. In other words: six women in ten on leaving the maternity unit, and still one in three a year later.

The longitudinal ultrasound follow-up of primiparous women gives the same trajectory with finer resolution: diastasis falls from 100 % of women at the end of pregnancy to 39 % at 6 months postnatally ². So four women in ten still have a diastasis at the 6^th month: spontaneously.

The distension of pregnancy and its retreat have been quantified in the same population of 84 primiparous women ¹². The orders of magnitude are worth knowing, because they completely reframe what a “large” diastasis is:

Two lessons. First, the supra-umbilical IRD can exceed 8 cm at term: the wall must open, and that is physiological. Second, the linea alba is widest 2 cm above the umbilicus, during pregnancy as well as afterwards, and in primiparous women the IRD can be considered normal at wider values than in nulliparous women ¹². A single 2 cm threshold applied at every level, in every woman, therefore makes no physiological sense. For the record, in healthy nulliparous women the maximum inter-recti distance is below 10 mm at every location, with pooled values of about 8,77 mm in the umbilical zone, 7,22 mm in the epigastric zone and 4,09 mm in the infra-umbilical zone ¹¹.

What spontaneous recovery does not do

Moderate evidence The point that is poorly conveyed to patients: the wall does not become nulliparous again. In the ultrasound follow-up of 115 postnatal women compared with 69 age-matched nulliparous women (day 1, 2 months, 6 months, 12 months), the rectus abdominis remains significantly thinner and wider, and the IRD significantly larger than in the controls at EVERY measurement time point (p < 0,0001 for the IRD at all four time points; p < 0,0478 and p = 0,0326 at 12 months for thickness and width). Most of the repair takes place over the first two months, the muscle thickens (p = 0,0003), width and IRD decrease (p < 0,0001 and p = 0,0002), but the values do not catch up with those of the controls at 12 months ²¹.

The same plateau is seen for function. In 40 women followed from 4-8 weeks to 6-8 months postnatally and compared with 20 matched nulliparous women, the IRD decreases significantly 2,5 cm above the umbilical ring (p = 0,013) and at its upper margin (p = 0,002), but neither the IRD nor abdominal muscle function had returned to normal values at 6 months ²². “It is better” does not mean “it is repaired”.

And in the very long term, the decline stops then reverses. In 1 000 women assessed by ultrasound at 3, 5, 10, 20 and 30 years postnatally, the prevalence of diastasis (criterion IRD > 2 cm) is 36 %, 31 %, 22 %, 26 % and 30 % ; with the criterion IRD > 3 cm, 13 %, 8 %, 6 %, 8 % and 10 % ³. The curve reaches its minimum at around 10 years postnatally then rises again. About one woman in ten keeps a diastasis > 3 cm thirty years later.

The bias this timeline imposes on any reading of a trial

This early spontaneous window is not just information for the patient: it contaminates the interpretation of the whole rehabilitation literature. Skoura's scoping review ³⁶ says so explicitly: most studies included women within the first 6 months postnatally, a period during which the spontaneous reduction in IRD may be confounded with the effect of the intervention ³⁶. An “excellent result” displayed by a protocol started at 6 weeks is, to an extent impossible to isolate, natural history.

This bias must be kept in mind when reading the next section, which is precisely the one where the temptation to overclaim is greatest.

Progression: when to start, and what to expect from exercise

Moderate evidence Starting early does better on anatomy. The most recent meta-analysis (9 RCTs, 450 participants, searched up to August 2025) shows that structured exercise programmes significantly reduce the IRD (mean difference −8,05 mm ; 95 % CI: −10,43 to −5,68; p < 0,05), and that interventions started before 3 months postnatally achieve a greater reduction (−10,2 mm; 95 % CI: −14,94 to −5,46) than late starts ³⁸. A reduction of nearly 1 cm is not cosmetic: it can tip a “moderate” diastasis into a “mild” one.

Low-quality evidence But the anatomical gain does not translate into a functional gain. In the same meta-analysis, on the Oswestry Disability Index (3 comparisons from 2 RCTs, n = 115), no difference between groups (MD: 0,82; 95 % CI: −2,75 to 4,38; p = 0,75; I² = 0 %) ³⁸. The message is uncomfortable but it has to be held: the gap closes a little, women are not made more functional as a result, within the time frames observed.

This dissociation is consistent with the rest of the corpus:

The practical conclusion is not “physiotherapy is useless”. It is: physiotherapy works on function, strength and lived experience, not on anatomical restoration of the linea alba ³⁹⁴¹. That is exactly what must be spelled out with a patient whose goal is morphological, on pain of selling a result the literature does not document.

Which exercises, and the end of the crunch trial

Moderate evidence The most useful point of the recent meta-analysis almost went unnoticed: no significant difference between types of training (p = 0,32), with a consistent advantage of structured exercise over no intervention or standard care ³⁸. In other words, the “transversus vs crunch” turf war is not settled by the data, what counts is training at all.

On the crunch specifically, the cleanest randomised controlled trial (PEDro score 8/10) tested a 12-week home programme containing head lifts in women with diastasis at 6-12 months postnatally: it neither worsened nor improved the IRD (mean difference of 1 mm at rest 2 cm above the umbilicus; 95 % CI: −1 to 4), without changing the severity of pelvic floor disorders or low back and pelvic girdle pain, while increasing the strength and thickness of the abdominal muscles ³². The classic contraindication to the crunch in moderate diastasis therefore does not stand up to the data.

This does not mean that every exercise does the same thing to the linea alba: they even do opposite things, and counter-intuitively so:

• In primiparous postnatal women (n = 38): the IRD above the umbilicus is significantly reduced during the abdominal crunch, whereas the IRD below the umbilicus is significantly wider during drawing-in (pulling the tummy in / transversus activation) than at rest ²⁴.
• In pregnant women with a diastasis ≥ 2,8 cm (n = 38, ultrasound at weeks 27 and 37): pelvic floor contraction increases the IRD by 2 mm (95 % CI: 2 to 3), drawing-in by 4 mm (3 to 5), the two combined by 5 mm (4 to 6); conversely the head lift decreases it by 3 mm (−4 to −2), the curl-up by 3 mm (−4 to −2), the diagonal curl-up by 4 mm (−5 to −3) ³⁵.

And above all: narrowing the gap is not the functional objective. In women with diastasis, the automatic curl-up narrows the IRD but distorts the linea alba more, whereas pre-activation of the transversus reduces the IRD less while distorting the linea alba less; the authors stress that this smaller narrowing by the transversus, advised against until then, could on the contrary favour abdominal mechanics through tension transfer ²⁵. Clinical translation: the physiotherapist who judges an exercise by eye, on the “gap closing”, is choosing the wrong criterion.

Return to sport: what is known, and what is not

Low-quality evidence Diastasis resolves whatever the level of activity resumed: including high impact. In a longitudinal prospective cohort of 504 women followed at 3, 6, 9 and 12 months postnatally (diastasis measured with callipers), grouped by their activity at 3 months, non-exercisers (n = 105), minimal low impact (n = 249), regular low impact (n = 117), high impact (n = 32), the sensation of vaginal heaviness and the diastasis decreased in every group. Non-exercisers, by contrast, reported more severe pelvic girdle pain, had a weaker pelvic floor, and their stress urinary incontinence increased while it remained stable or improved in the active groups ¹⁰. The authors explicitly invite physiotherapists to encourage an early return to low-impact activity.

Low-quality evidence A dedicated protocol allows an early return to sport in sportswomen. A prospective observational pilot study in 37 sportswomen (training ≥ 3 times/week with amateur or competitive events), IRD measured by ultrasound at 4 sites (xiphoid, supra-umbilical, umbilical, infra-umbilical) at inclusion (≈ 3 months postnatally), at 2 months and at 4 months; protocol of 3 weekly sessions (1 supervised + 2 at home). The patients improve on all 4 measurements and return to sport early ³³. A crucial point for triage: of the 37, 6 were referred for surgery, 2 hernias and 4 diastases > 4 cm, and 31 benefited from conservative treatment.

In elite athletes, the actual return is far earlier than any rehabilitation reference point: in a comparative study of 34 Norwegian elite athletes (mean age 33,1 years) and 34 active controls (31,5 years), the majority of the athletes and one control in three returned to sport or exercise between 0 and 6 weeks postnatally ; four athletes had stress fractures postnatally, and the athletes described themselves as dissatisfied with the advice received on strength training and nutrition during pregnancy ⁴⁴. Caution: small sample, limited generalisability, and this study did not measure diastasis: it documents a practice, not a safety margin.

Moderate evidence The lists of “forbidden” exercises circulating on social media, by contrast, are actively harmful. A mixed-methods study screened 1 000 Instagram posts on diastasis, of which 28 were included: 61 % (n = 17) offered recommendations that were not evidence-based and only 7,1 % (n = 2) cited a scientific source, quality being rated poor on the QUEST tool. The twenty women with diastasis who were interviewed described the ubiquity of the prescriptive “do / do not” lists, and reported confusion, misinformation and nocebo effects ; recommendations consistent with the literature influenced only 20 % of them positively (n = 4) ³⁷. Part of the rehabilitation work therefore consists literally of defusing what the patient has read before arriving.

Prevention during pregnancy: neither a promise nor a prohibition

Moderate evidence The question patients ask is twofold: “can I avoid diastasis?” and “do I risk making it worse by moving?”. Both answers are now fairly clear.

Worsening: no. A randomised trial included 96 pregnant women (≥ 18 years, at 24 weeks of gestation, with an IRD ≥ 28 mm at rest and/or a visible protrusion) allocated to a 12-week programme of abdominal and pelvic floor exercises, or to a control group with no intervention. The effect of the intervention was 2 mm (95 % CI: −2 to 7) immediately after the programme: negligible, both at the end of the intervention and at 6 weeks postnatally ³⁴. The very title of the trial is the message: pregnant women can train the abdominals and the pelvic floor without increasing diastasis.

Prevention: weak signal. The landmark systematic review (8 studies, 336 women) finds a favourable antenatal signal, a 35 % reduction in the presence of diastasis (RR 0,65; 95 % CI: 0,46–0,92), but concludes cautiously that non-specific exercise “may or may not” help prevent or reduce diastasis in the peri- and postnatal periods, given the poor methodological quality of the included studies ⁴⁰.

Finally, a trajectory marker to give to women worried about seeing the gap grow during the 3^rd trimester: in pregnant women with diastasis, the IRD increases naturally by 8 mm on average (95 % CI: 6 to 9) between weeks 27 and 37 ³⁵. That is not a failure of the programme, it is pregnancy.

The next pregnancy: the best-established risk factor

Moderate evidence If a single variable had to be retained from the whole literature on risk factors, it would be the number of pregnancies. A literature review concludes that among all the factors proposed, only the number of pregnancies, BMI and diabetes emerge as the most plausible, and that the more pregnancies a woman has had, the greater the risk of diastasis ¹⁶. The cohorts confirm this:

Two qualifications not to be glossed over. First, caesarean section is not an unequivocal factor : Cavalli's review notes that it “appears to be a risk factor only in women who have given birth twice” ¹⁶, whereas two cohorts find it an independent factor ¹³ or as the mirror image of the protective effect of vaginal birth ¹⁵. Second, on age, the results are contradictory: not significant in Mota and Sperstad, a risk factor in Spitznagle but protective in Wu ¹⁶, while He 2025 finds it significant. So we do not conclude in place of the data.

And the “obvious” factors are not confirmed. In the ultrasound follow-up of 84 primiparous women, at 6 months postnatally, no statistically significant difference in pre-pregnancy BMI, gestational weight gain, the baby's birth weight or abdominal circumference between women with and without diastasis ². The same finding in He 2025: fetal weight, pre-pregnancy BMI and postnatal BMI not significant in the final model (p > 0,05). In other words, the patient who blames herself for having “put on too much” is very probably wrong.

In the long term, by contrast, parity and metabolic background do come out: in 1 000 women, at 3 years the number of deliveries and twin pregnancies are risk factors (p = 0,000 and 0,001); at 10 years, BMI and the number of deliveries (p = 0,000); at 20 and 30 years, diabetes (p = 0,000 and 0,004) ³.

What to do with this clinically. You do not tell a woman that a new pregnancy will “ruin” her abdomen: you tell her that parity is the best-documented factor ¹⁶¹⁵¹⁴, that the diastasis will again largely resolve ¹², that pelvic floor strength appears protective ¹⁵, and that nothing in the data indicates she should stop moving: neither during ³⁴, nor after ¹⁰. If a surgical plan exists, the question of obstetric timing must be raised beforehand, with the surgeon.

Postnatal support: defusing without trivialising

This is probably the aspect where the physiotherapist adds the most value, and the one least measured by trials.

What should be defused, because the data allow it

Strong evidence Diastasis is not the cause of postnatal low back pain. In the cohort of 300 primiparous women, at 12 months postnatally, no difference in lumbopelvic pain between women with and without diastasis (p = 0,10) ¹. Presenting it straight away as the culprit behind back pain is a documented error.

Strong evidence Diastasis is not a marker of pelvic floor dysfunction. The Norwegian prospective cohort finds no significant difference in pelvic floor variables at 6 weeks, 6 months and 12 months postnatally between women with and without diastasis, nor in urinary incontinence at any time point; counter-intuitively, at 6 weeks prolapse was significantly more frequent in women WITHOUT diastasis (15,9 % vs 4,1 %; p = 0,001) ²⁶. The result withstands the severity test: in a retrospective cohort of 229 women during the first year postnatally, no difference in urinary incontinence or prolapse, whatever IRD threshold was used (20, 30, 40 or 50 mm) ²⁷. When an association is found, it is weak: r = 0,283 with stress urinary incontinence symptoms, r = −0,278 with maximum voluntary contraction, r = −0,274 with its duration, and no correlation with the area of the urogenital hiatus ²⁸.

What should not be trivialised, because the data show that too

Moderate evidence The impact is to be read somewhere other than the pelvic floor. In primiparous women assessed postnatally, diastasis was not correlated with morphological changes of the pelvic floor (imaging), but was associated with a significantly higher PFDI-20 urinary symptom score (12,5 ± 22,8 without diastasis vs 26,8 ± 18,2 with; p = 0,01); and extensive diastases (grades 2-3) had significantly reduced abdominal strength and endurance: dynamic endurance test 13,4 ± 11,8 vs 6,46 ± 4,59 repetitions (p = 0,025), manual muscle testing 4 vs 3 (p = 0,04) ²⁹. An extensive diastasis really does come with weak abdominals.

On quality of life, the outcome is more relevant than pelvic floor symptoms: in 253 patients, severe diastasis had a significant impact on the HerQLes score at birth (p = 0,001) and at 3-6 months (p = 0,01), but no effect on pelvic floor symptoms measured with the FPFQ ¹⁷.

Moderate evidence Body image is massively underestimated in clinic. Cross-sectional study of 460 primiparous women at 6-8 months postnatally: 73,3 % reported having worried during pregnancy about the appearance of their abdomen after giving birth ; the mean degree of concern about their current abdominal appearance was 5,5/10 (SD 2,4) ; nearly 80 % felt their abdominal muscles were weaker than before pregnancy ; and among the 20,9 % (n = 96) reporting a midline protrusion, significantly more women described themselves as weakened than those without protrusion ³¹.

And the lived experience goes far beyond the musculoskeletal field. A mixed-methods study reports a negative effect of diastasis on quality of life, functional capacity and urogynaecological and digestive health, along with an emotional impact involving altered body image and poor perceived health: the authors describe feelings of abandonment by health institutions, shame, sadness, helplessness, a lack of self-esteem, resignation and social pressure ³⁰. These dimensions belong to the physiotherapy interview; ignoring them repeats the abandonment described.

How to measure, so as not to manufacture false progress

Moderate evidence If you follow a patient over twelve months, the measurement method must be stable, otherwise you are following noise. The systematic review of methods (13 studies) supports ultrasound and callipers as the adequate methods, with low measurement error above the umbilicus; the fingerbreadth method offers only moderate inter-rater agreement (63 %; weighted Kappa = 0,53) ⁶. 2D ultrasound has good to very good test-retest reproducibility (ICC 0,74 to 0,90), the only exception being the measurement 2 cm below the umbilicus during the crunch (ICC 0,50); intra-observer reproducibility on the same images exceeds 0,90 ⁹.

The measurement site counts as much as the tool: at rest, the ICC reaches 0,91 at 5 cm above the umbilicus but falls to 0,72 at the upper edge of the umbilicus; on head lift, it goes from 0,96 (5 cm above) to 0,63 at the umbilical level, hence the recommendation to favour standardised supra-umbilical measurement sites ⁷. And remember that the reference definition measures at three levels, 4,5 cm above, at, and 4,5 cm below the umbilicus, supine with a crunch ¹ : measurement is not taken at a single point.

When recovery does not come: the referral threshold

Moderate evidence Physiotherapy is the first therapeutic tier for symptomatic diastasis; surgery comes only second-line. In practice: if the patient comes back after 2 to 6 months of conservative treatment with persistent symptoms, referral to a surgeon may be considered, and, where possible, surgery should wait until at least 1 year postnatally, since some patients experience spontaneous resolution during the first year ⁴³. This one-year wait is not stalling: it is the direct translation of the Sperstad 2016 curve.

The profile that tips over is not “the widest diastasis”, it is the training-resistant diastasis. The only randomised trial comparing surgery with muscle training (86 patients: 29 retromuscular mesh, 27 double-row plication, 32 on a 3-month training programme) shows at 1 year a significant muscle gain in EVERY group, including the training group, but the perceived strength gain was significantly greater in the two operated groups, and the patients in the training group continued to have bodily pain at follow-up ⁴⁵. Physiotherapy genuinely strengthens the wall; it is the persistence of pain and discomfort despite that strengthening which marks out the candidate subgroup. This profile is precisely the one documented in the cohort of 60 postnatal women operated on for “training-resistant canister dysfunctions”, in whom plication improved, at 3 years, every parameter of the Disability Rating Index (p < 0,001), canister strength and stability (p < 0,001), back muscle strength (p < 0,001) and abdominal strength (p = 0,002), urinary incontinence (UDI-6 p < 0,001; IIQ-7 p = 0,004) and quality of life (SF-36) ⁴⁶.

Finally, what must be said honestly to a patient considering surgery: there is no consensus on the surgical indications or on the optimal technique ⁴⁷. In 931 operated patients (18-70 years, follow-up from 3 weeks to 20 years), recurrence is reported in 5 %, the most frequent complication being seroma (7 %), followed by abdominal hypoaesthesia (6 %) and surgical site infection (2 %); chronic pain is reported in 4 % and satisfaction is high overall ⁴⁸. On plication performed during an abdominoplasty, the functional benefit is more consistent than the strength gain: in 497 patients (mean age 44,5 years; 94,4 % women), the 4 studies that used the SF-36 show an improvement in the physical function subscale, but only 2 of the 3 studies measuring abdominal strength find a significant improvement, for an overall complication rate of 17,0 % ⁴⁹.

📋 What do concrete case studies teach us?

Warning: the two cases presented below are entirely fictional. They are neither real patients nor vignettes taken from a published series. They are teaching constructions, assembled solely from the confirmed data presented earlier in this article: the prevalence figures, measurement protocols, normative percentiles and intervention effects cited all come from referenced studies, but their arrangement into a “patient story” is illustration. No clinical conclusion should be drawn from the cases themselves: they serve to make a piece of reasoning visible, what is measured, where, with what tool, what is said to the patient, and how the load is progressed.

Why go via a case? Because diastasis is probably one of the presentations in perinatal rehabilitation where the gap is greatest between what the literature says and what the patient arrives with. A mixed-methods analysis of 1 000 Instagram posts on the subject (28 included) showed that 61 % of the posts offered recommendations that were not evidence-based and that only 7,1 % cited a scientific source, with quality rated poor on the QUEST tool; the women interviewed reported confusion, misinformation and nocebo effects, while recommendations consistent with the literature influenced only 20 % of them positively ³⁷. Clinical reasoning therefore begins, very concretely, with a piece of defusing work.

Illustrative case no. 1: Léa, 32 years old, primiparous, 4 months postnatally

The reason for consulting

Léa (fictional case) gave birth vaginally 4 months ago. She is consulting for what she describes as “a hole above my navel” and a belly that “points into a triangle” when she gets up from lying down. She stopped all abdominal activity after reading that she must “never, ever do a crunch”. She also attributes to her diastasis the low back pain that started at the end of pregnancy. When asked, she rates her aesthetic concern at 7/10.

This profile is in no way exceptional. In a cross-sectional study of 460 primiparous women at 6-8 months postnatally, 73,3 % reported having worried already during pregnancy about the appearance of their abdomen after giving birth; the mean degree of concern about their current abdominal appearance was 5,5/10 (SD 2,4), and nearly 80 % felt their abdominal muscles were weaker than before pregnancy. The 20,9 % of women reporting a midline protrusion described themselves as weakened significantly more often than those without protrusion ³¹.

What is measured, and above all where

The first reflex is not to measure at a single point. The reference protocol of the Norwegian prospective cohort defines diastasis as a palpated separation of at least 2 fingerbreadths, assessed at three levels : 4,5 cm above the umbilicus, at the umbilicus, and 4,5 cm below, with the patient supine performing an abdominal crunch ¹. Measuring only “at the navel” means ignoring two thirds of the problem.

The second reflex is to know the worth of your own tool. Moderate evidence A systematic review of measurement methods (13 studies: fingerbreadth, tape measure, callipers, ultrasound, CT, MRI) concludes that ultrasound and callipers are the adequate methods, with low measurement error above the umbilicus; the fingerbreadth method offers only moderate inter-rater agreement: 63 %, weighted Kappa = 0,53 ⁶. In other words: the fingers are for screening, not for fine longitudinal follow-up.

The third reflex is topographical. Strong evidence The reliability of ultrasound measurement depends massively on the site: at rest, the ICC reaches 0,91 at 5 cm above the umbilicus but falls to 0,72 at the upper edge of the umbilicus; on head lift, it goes from 0,96 (5 cm above) to 0,63 at the umbilical level ⁷. Another series finds good to very good test-retest reproducibility (ICC 0,74 to 0,90), with one exception : the measurement 2 cm below the umbilicus during the crunch, whose ICC collapses to 0,50 ⁹. Practical conclusion: standardise supra-umbilical sites, note the exact position, and be wary of umbilical and infra-umbilical measurements in contraction.

Léa's (fictional) assessment: palpation: 2 to 3 fingerbreadths at 4,5 cm above the umbilicus, 2 at the umbilical level, fewer than 2 infra-umbilically. 2D ultrasound: 26 mm at 2 cm above the umbilicus at rest, 19 mm at 5 cm above, 14 mm at 2 cm below. Search for a painful or irreducible midline bulge: negative. Abdominal testing: dynamic endurance at 7 repetitions, manual muscle testing at 3.

Interpreting: against what?

This is where most of the reasoning happens. Comparing Léa with a nulliparous woman would be a mistake. Moderate evidence The normative values in healthy nulliparous women place the maximum inter-recti distance below 10 mm at every location, with pooled values of about 8,77 mm in the umbilical zone, 7,22 mm in the epigastric zone and 4,09 mm infra-umbilically ¹¹. But in primiparous women, the longitudinal ultrasound follow-up of 84 women gives, at 6 months postnatally, 20^th-80^th percentiles of 9-21 mm at 2 cm below the umbilicus, 17-28 mm at 2 cm above and 12-24 mm at 5 cm above: the authors explicitly conclude that in primiparous women the inter-recti distance “can be considered normal at wider values than in nulliparous women”, and that the linea alba is widest 2 cm above the umbilicus ¹². Léa's 26 mm at 2 cm above the umbilicus therefore fall within the 20-80 range for primiparous women. That reframing alone changes the appointment.

What is explained to the patient

• “It is common, and it largely resolves on its own.” In the cohort of 300 primiparous women, prevalence was 33,1 % at 21 weeks of pregnancy, 60,0 % at 6 weeks postnatally, 45,4 % at 6 months and 32,6 % at 12 months ¹. An ultrasound follow-up of primiparous women finds a fall from 100 % at the end of pregnancy to 39 % at 6 months ². The scale of the retreat is spectacular: at the end of pregnancy (weeks 35-41), the 20^th-80^th percentiles ranged from 54-86 mm at 2 cm above the umbilicus, against 17-28 mm at 6 months postnatally ¹².
• “But spontaneous recovery plateaus, and it is incomplete.” In 115 women followed by ultrasound against 69 age-matched nulliparous women, the rectus abdominis remains significantly thinner and wider, and the inter-recti distance significantly larger, at every time point: day 1, 2 months, 6 months and 12 months (p<0,0001 pour l'IRD aux quatre temps); l'essentiel de la récupération se fait sur les 2 premiers mois, et les valeurs ne rejoignent pas celles des témoins à 12 mois ²¹. Another follow-up shows a significant decrease in IRD 2,5 cm above the umbilical ring (P = 0,013) and at its upper margin (P = 0,002), without a return to normal values at 6 months ²². The message is not “it will close”, it is “it is improving, and the wall will not become nulliparous again”.
• “Your diastasis is not the cause of your low back pain.” In the same cohort, at 12 months postnatally, no significant difference in lumbopelvic pain was found between women with and without diastasis (p = 0,10) ¹.
• “Nor does it put your pelvic floor at risk.” Women with diastasis had neither a weaker pelvic floor, nor more urinary incontinence, nor more prolapse at 6 weeks, 6 months and 12 months; at 6 weeks, prolapse was even significantly more frequent in women without diastasis (15,9 % vs 4,1 %, p = 0,001) ²⁶. This result withstands the severity test: in 229 women, no difference in incontinence or prolapse whatever the threshold used: 20, 30, 40 or 50 mm ²⁷. And when an association is found, it is weak (r = 0,283 with stress incontinence symptoms; r = -0,278 with maximum voluntary contraction) ²⁸.
• “The crunch is not forbidden.” Strong evidence A randomised controlled trial with a PEDro score of 8/10, in women with diastasis between 6 and 12 months postnatally, shows that a 12-week home programme containing head lifts neither worsened nor improved the inter-recti distance (mean difference 1 mm at rest 2 cm above the umbilicus, 95 % CI -1 to 4), while increasing the strength and thickness of the abdominal muscles ³².

How progression works

Three principles guide Léa's programming (fictional case).

1. You load, and you do not delay. Moderate evidence A meta-analysis of 9 RCTs (450 participants) shows that structured exercise programmes significantly reduce the inter-recti distance (mean difference -8,05 mm; 95 % CI -10,43 to -5,68; p < 0,05), avec un effet supérieur quand l'intervention débute before 3 months postnatally (-10,2 mm; 95 % CI -14,94 to -5,46) and, a crucial point for programming, no significant difference between types of training (p = 0,32) ³⁸. A systematic review with meta-analysis in the BJSM, searching eight databases up to 12 January 2024, concludes in the same direction with “low” GRADE certainty: abdominal training reduces the inter-recti distance compared with no exercise ⁴². Low-quality evidence

2. You know what each exercise does, and it is not uniform. In 38 primiparous women, the IRD above the umbilicus was significantly reduced during the crunch, whereas the IRD below the umbilicus was significantly wider during drawing-in than at rest ²⁴. In pregnant women with diastasis, the acute effects are quantified: pelvic floor contraction +2 mm (95 % CI 2 to 3), drawing-in +4 mm (3 to 5), the two combined +5 mm (4 to 6); conversely head lift -3 mm (-4 to -2), curl-up -3 mm (-4 to -2), diagonal curl-up -4 mm (-5 to -3) ³⁵. But narrowing the gap is not the objective: the automatic curl-up narrows the IRD while distorting the linea alba more, whereas pre-activation of the transversus reduces the IRD less while distorting the linea alba less, and the authors suggest that this smaller narrowing, advised against until then, could on the contrary favour abdominal mechanics through tension transfer ²⁵.

3. You do not forget the pelvic floor, not in order to “close”, but because it is protective. In a large cohort, vaginal birth is associated with a reduced risk of diastasis (OR 0,45; 95 % CI 0,40-0,51), as is type I pelvic floor strength of grade II to IV ¹⁵.

(Fictional) follow-up at 12 weeks: IRD at 2 cm above the umbilicus: 21 mm (against 26). Dynamic endurance: 14 repetitions (against 7). Aesthetic concern: 3/10. Running resumed.

And an indispensable honesty in interpreting this “success”. A scoping review (28 studies) stresses that most studies included women within the first 6 months postnatally, a period during which the spontaneous reduction in IRD may be confounded with the effect of the intervention ³⁶. Part of Léa's result is natural history. Saying so is a clinical act, not false modesty: it protects the patient from believing that one particular protocol “worked”, and therefore from believing that another would have made things worse.

Illustrative case no. 2: Sonia, 39 years old, second caesarean section, 14 months postnatally

The reason for consulting

Sonia (fictional case) gave birth to her second child 14 months ago, by caesarean section (both of them). An amateur triathlete, she has gone back to swimming but is stuck on running and strength work. She describes a permanently visible midline bulge, a sense of trunk instability on exertion, and discomfort when carrying her older child. She did “the exercises” found online for 8 months, with no visible change. She says she feels “abandoned” and avoids the changing rooms.

This dimension is not an optional extra. A mixed-methods study reports a negative effect of diastasis on quality of life, functional capacity and urogynaecological and digestive health, along with an emotional impact involving altered body image, feelings of abandonment by health institutions, shame, sadness, helplessness, lack of self-esteem, resignation and social pressure ³⁰. In 253 patients followed after giving birth, severe diastasis had a significant impact on quality of life (HerQLes score) at birth (p = 0,001) and at 3-6 months (p = 0,01), but no effect on pelvic floor symptoms measured with the FPFQ ¹⁷.

What is measured, and what the risk profile says

Sonia's profile methodically ticks the documented factors:

• Multiparity : more than twice the risk compared with nulliparity (OR 2,67; 95 % CI 1,30-5,45) ¹⁵ ; the number of births doubles the risk (OR 2,09; 95 % CI 1,30-3,37; p = 0,002) ¹⁴. A literature review moreover retains the number of pregnancies, BMI and diabetes as the most plausible factors ¹⁶.
• Caesarean section : independent risk factor, incidence 2,297 times higher (OR 2,297; 95 % CI 1,327-3,978; p = 0,003) in 534 women ¹³ ; in mirror image, vaginal birth is protective (OR 0,45) ¹⁵. Caesarean section (p = 0,05) and multiparity (p = 0,04) are among the factors for persistence of the diastasis ¹⁷. A qualification: one review notes that caesarean section “appears to be a risk factor only in women who have given birth twice” ¹⁶, which is precisely Sonia's case.
• Age : each additional year increases the risk by 10 % (OR 1,10; 95 % CI 1,04-1,16; p = 0,002) ¹⁴. To be qualified: the results are contradictory across cohorts ¹⁶.
• What is NOT a factor, contrary to the prevailing discourse : in He 2025's final model, fetal weight, pre-pregnancy BMI and postnatal BMI were not significant (p > 0,05). At 6 months postnatally, no significant difference in pre-pregnancy BMI, gestational weight gain, birth weight or abdominal circumference between women with and without diastasis ². Do not place on the patient a weight-related responsibility the data do not support.

Sonia's (fictional) assessment: palpation: 4 fingerbreadths at the umbilical level, 3 at 4,5 cm above, 3 below. Ultrasound: 42 mm at the umbilical level, 38 mm at 2 cm above. This topography is consistent with ShearWave elastography of 36 postnatal women with diastasis, in whom the maximum separation was located at the umbilicus (4,59 ± 1,14 cm) ²⁷. Testing: dynamic endurance at 6 repetitions, manual muscle testing at 3.

These strength figures are not incidental: in primiparous women, extensive diastases (grades 2-3) showed significantly reduced abdominal strength and endurance, dynamic endurance test 13,4 ± 11,8 vs 6,46 ± 4,59 repetitions (p = 0,025); manual muscle testing 4 vs 3 (p = 0,04), and a significantly higher PFDI-20 urinary symptom score (12,5 ± 22,8 without diastasis vs 26,8 ± 18,2 with, p = 0,01), with no correlation with morphological changes of the pelvic floor on imaging ²⁹. With Sonia, then, you follow strength and symptoms, not the IRD alone.

The flag not to miss

Before any programming: look for a hernia. Strong evidence In a multicentre retrospective study over 10 years covering 1 294 cases of diastasis, 35,8 % of the women had one or more hernias, umbilical hernia being the most prominent type; in women, age (OR 1,51 [1,33-1,72]; p = 0,000) and smoking (OR 1,66 [1,13-2,44]; p = 0,010) were risk factors for an associated hernia ⁴. Sonia is 39: she is in the target group.

Why this changes everything: in 231 patients operated on for a small umbilical or epigastric hernia (<2 cm) par simple suture sans filet, le taux de récidive était de 31,2 % (29/93) with an associated diastasis against 8,3 % (9/108) without (p < 0.001); the authors strongly recommend looking for a diastasis before surgery and using a prosthetic reinforcement where one is found ⁵. A painful or irreducible midline bulge calls for medical and surgical referral with no delay for physiotherapy. In Sonia's (fictional) case, the bulge is reducible and painless: we continue.

What is explained, and why physiotherapy does not “close” it

Sonia asks why 8 months of exercises changed nothing about her belly. The answer lies in the nature of the tissue.

Diastasis is not only a mechanical distension: it is also a qualitative alteration of the connective tissue. In a case-control study (18 women with diastasis, 18 without, midline fascia samples, immunohistochemistry), type I and type III collagen were both significantly less abundant (p < 0,001) — collagène I sus-ombilical 244,5 ± 73,5 kpixels vs 381,1 ± 101,1 chez les témoins; collagène III sus-ombilical 54,3 ± 33,1 vs 154,9 ± 59,4 ²³. The linea alba is also anisotropic: under a physiological abdominal pressure of about 20 kPa, its Young's modulus is around 50 kPa transversely against 20 kPa longitudinally, a compliance ratio of roughly 2:1, with non-linear elastic behaviour ²⁰. Its structure combines transverse fibres, which “counterbalance” intra-abdominal pressure, and oblique fibres, mainly loaded during trunk movements ¹⁸ ; under tension, the ventral oblique fibres reorient towards the axis of traction, progressively increasing stiffness, while elastin, in a superficial layer, provides the elastic recoil ¹⁹. And the wall itself reorganises: on elastography, stiffness is significantly lower in the rectus abdominis (p = 0,003) and the external oblique (1,65 ± 0,15 vs 1,79 ± 0,14, p = 0,001) but significantly higher in the transversus (p < 0,001) chez les femmes avec diastasis ²⁷.

Hence the central message, to be given without hedging to a patient whose goal is morphological: Moderate evidence a systematic review of 20 articles (1 691 patients: 1 591 surgery / 100 physiotherapy) concludes that no physiotherapy programme has shown complete resolution of diastasis measured at rest ; physiotherapy achieves a limited reduction in IRD during muscle contraction, whose impact on satisfaction, appearance and function remains uncertain ³⁹. A systematic review with meta-analysis of 16 trials (698 women) points the same way: conservative interventions do not produce a clinically significant reduction in IRD, but abdominal exercises may provide other physical and psychosocial benefits ⁴¹. And even when the anatomical gain exists (-8,05 mm), it does not translate into superior functional recovery: on the Oswestry Disability Index, no difference between groups (MD 0,82; 95 % CI -2,75 to 4,38; p = 0,75; I² = 0 %) ³⁸.

How progression works, and when to refer

The sequence is clear in the literature: physiotherapy is the first tier for a symptomatic diastasis with no associated hernia; if the patient comes back after 2 to 6 months of conservative treatment with persistent symptoms, referral to a surgeon may be considered, and, where possible, surgery should wait until at least 1 year postnatally, since some patients experience spontaneous resolution during the first year ⁴³. Sonia is at 14 months: the spontaneous resolution window is well past, but a structured conservative trial remains the prerequisite: all the more so because her 8 months of self-administered online exercises do not constitute an assessable therapeutic trial.

She is therefore offered a structured protocol. In a prospective observational pilot study in 37 sportswomen (training ≥ 3 times/week with competition), the IRD was measured by ultrasound at 4 sites (xiphoid, supra-umbilical, umbilical, infra-umbilical) at inclusion (≈ 3 months postnatally), at 2 months and at 4 months, with 3 weekly sessions (1 supervised + 2 at home) ; the patients improved on all 4 measurements and returned to sport early. A point directly transposable to Sonia's triage: of these 37 women, 6 were referred for surgery: 2 for hernia, 4 for a gap greater than 4 cm ³³. Sonia's 42 mm place her in that subgroup.

(Fictional) follow-up at 4 months: umbilical IRD: 36 mm. Dynamic endurance: 15 repetitions. Running resumed to 40 minutes. But : the midline bulge is unchanged, discomfort persists when carrying loads, quality of life is still impaired.

This picture (improved strength, persistent pain) is exactly the one documented by the only randomised trial comparing surgery with muscle training (86 patients: 29 retromuscular mesh, 27 double-row plication, 32 on a 3-month training programme). At 1 year, a significant muscle gain was achieved in every group, including the training group; but the perceived strength gain was significantly greater in the two operated groups, and the patients in the training group continued to have bodily pain at follow-up ⁴⁵. The subgroup that is a candidate for surgery is therefore not “the one with the big gap”: it is the one whose pain and discomfort persist despite effective strengthening. A cohort of 60 postnatal women with diastasis and “training-resistant abdominal canister dysfunctions”, operated on by plication of the linea alba, shows at 3 years an improvement in every parameter of the Disability Rating Index (p < 0,001), de la force et stabilité du caisson (p < 0,001), de la force des muscles du dos (p < 0,001) et des abdominaux (p = 0,002), de l'incontinence urinaire (UDI-6 p < 0,001; IIQ-7 p = 0,004) et de la qualité de vie (SF-36), de façon stable entre 1 et 3 ans ⁴⁶.

The fair information to give before referring. There is no surgical consensus: a PRISMA systematic review (37 studies, 45 techniques) explicitly notes the absence of consensus on repair indications and on the optimal technique, with no significant difference in complications (p = 0,165) or recurrences (p = 0,133) between open and laparoscopic approaches after adjustment for concomitant hernia repair ⁴⁷. In 931 operated patients (18-70 years, follow-up from 3 weeks to 20 years), recurrence is reported in 5 %; the most frequent complication is seroma (7 %), followed by abdominal hypoaesthesia (6 %) and surgical site infection (2 %); chronic pain is reported in 4 % ⁴⁸. On plication performed during an abdominoplasty (7 articles, 497 patients, 94,4 % women), the SF-36 physical function subscale improves in the 4 studies that used it, but only 2 of the 3 studies measuring abdominal strength show a significant improvement, for an overall complication rate of 17,0 % ⁴⁹.

What these two trajectories have in common

Three constants emerge from these two constructions.

First, you never measure “the” diastasis. You measure a distance, at a given site, with a tool whose ICC you know, in a given position, and you compare it with a reference matched to the patient's parity. The difference between an ICC of 0,96 and one of 0,63 for 5 cm of transducer movement ⁷ is larger than most published intervention effects.

Second, you systematically decouple anatomy from function and lived experience. The anatomical gain of -8,05 mm produces no gain on the ODI ³⁸ ; the IRD does not correlate with morphological changes of the pelvic floor but does correlate with PFDI-20 urinary symptoms ²⁹ ; severe diastasis degrades the HerQLes without touching the FPFQ ¹⁷. Three outcomes, three trajectories.

Finally, you move. In 504 women followed at 3, 6, 9 and 12 months postnatally (diastasis measured with callipers), grouped into non-exercisers (n = 105), minimal low impact (n = 249), regular low impact (n = 117) and high impact (n = 32), the sensation of vaginal heaviness and the diastasis decreased in every group; non-exercisers, by contrast, reported more severe pelvic girdle pain, had a weaker pelvic floor, and saw their stress urinary incontinence increase while it remained stable or improved in the active women ¹⁰. During pregnancy, a randomised trial in 96 women (IRD ≥ 28 mm at rest and/or visible protrusion) shows that a 12-week programme of abdominal and pelvic floor exercises has a negligible effect, 2 mm (95 % CI -2 to 7), that is, neither a demonstrated preventive benefit nor any worsening ³⁴ ; a moderate preventive signal nevertheless exists antenatally (a 35 % reduction in the presence of diastasis, RR 0,65; 95 % CI 0,46-0,92), on low-quality evidence and with a cautious conclusion: non-specific exercise “may or may not” help ⁴⁰. Low-quality evidence

🧭 How do you apply this in practice?

The whole clinical difficulty of diastasis recti abdominis lies in a gap: between what the patient comes looking for (“close the hole”) and what the literature allows us to promise (improving function, lived experience and strength, without anatomical restoration). The role of the physiotherapist and the midwife is therefore as much to reframe the goal as to deliver an exercise. This section offers a decision algorithm, the messages to hold to in session, the most frequent pitfalls, and the objective criteria for referral.

1. The decision algorithm, in five steps

The sequence proposed below follows the logic of the available data: first date it, then measure it properly, then attribute (or not) the symptoms to the diastasis, and finally treat and reassess.

2. Measuring: where, how, and what it is worth

The reference technique

The diagnostic criterion used in the landmark cohort is a palpated separation of at least 2 fingerbreadths, assessed at three levels (4,5 cm above the umbilicus, at the umbilicus, and 4,5 cm below), with the patient supine performing an abdominal crunch ¹. The essential practical point: measurement is not taken at a single point. An abdomen that is “normal” at the umbilicus may be diastasic 4,5 cm higher up, and vice versa.

Choosing your tool (and knowing its limits)

The location trap

Ultrasound reliability is not uniform along the linea alba. At rest, the ICC reaches 0,91 at 5 cm above the umbilicus but falls to 0,72 at the upper edge of the umbilicus ; on head lift, it goes from 0,96 to 0,63 ⁷. The same signal in Mota ⁹ : the only exception to good reproducibility is the measurement 2 cm below the umbilicus during the crunch (ICC 0,50).

Practical recommendation: favour standardised supra-umbilical measurement sites, and do not base a patient's follow-up on a measurement taken right at the umbilical level during a crunch.

What should the figure be compared with?

Three reference points, not to be confused:

• In healthy nulliparous women, the maximum IRD reported on ultrasound is below 10 mm at every location, with pooled values of about 8,77 mm in the umbilical zone, 7,22 mm in the epigastric zone and 4,09 mm infra-umbilically ¹¹.
• In primiparous women at 6 months postnatally, the 20^th–80^th percentiles are 9–21 mm at 2 cm below the umbilicus, 17–28 mm at 2 cm above and 12–24 mm at 5 cm above ¹². The authors explicitly conclude that in primiparous women the IRD can be considered normal at wider values than in nulliparous women, and that the linea alba is widest 2 cm above the umbilicus, during pregnancy as well as postnatally.
• At the end of pregnancy, these same percentiles are 49–79 mm, 54–86 mm and 44–79 mm ¹² : the distension is massive, and its spontaneous retreat considerable.

3. The key messages to deliver in session

These messages are not “communication”: they are interventions in their own right, in a condition where the nocebo effect of social media is documented ³⁷.

Message 1: “Your diastasis is probably not the cause of your back pain”

In the prospective cohort of 300 primiparous women, no difference in lumbopelvic pain was observed at 12 months between women with and without diastasis (p = 0,10) ¹. Defusing here is not cheap reassurance: it is correcting a mistaken causal attribution that misdirects the whole of care.

Message 2: “Closing the gap will not protect your pelvic floor”

The Norwegian cohort finds no difference in pelvic floor variables, urinary incontinence or prolapse between women with and without diastasis, at 6 weeks, 6 months and 12 months, and, counter-intuitively, at 6 weeks prolapse was even significantly more frequent in women without diastasis (15,9 % vs 4,1 %, p = 0,001) ²⁶. The absence of a link withstands the severity test: in a cohort of 229 women, no difference in incontinence or prolapse whatever the threshold used (20, 30, 40 or 50 mm) ²⁷. When an association is found, it is weak : r = 0,283 with stress urinary incontinence symptoms, r = −0,278 with maximum voluntary contraction ²⁸.

A qualification not to be erased : reported urinary symptoms (PFDI-20) were higher in the diastasis group (26,8 ± 18,2 vs 12,5 ± 22,8, p = 0,01), with no correlation with morphological changes of the pelvic floor on imaging ²⁹. And type I pelvic floor strength of grade II to IV is associated with a reduced risk of diastasis ¹⁵: an argument for working the pelvic floor, but for its own sake.

Message 3: “Part of the journey happens without us, and part of it will not happen at all”

Spontaneous recovery is real but early and incomplete. The rectus abdominis thickens (p = 0,0003) and the IRD decreases (p = 0,0002) over the first 2 months, but none of these values catches up with those of nulliparous controls at 12 months: the rectus abdominis remains thinner and wider, and the IRD larger, at day 1, 2, 6 and 12 months ²¹. The same conclusion in Liaw ²² : the IRD decreases significantly 2,5 cm above the umbilical ring (p = 0,013) and at its upper margin (p = 0,002), without reaching normal values at 6 months.

Message 4: “The goal is function, not closure”

No physiotherapy programme has shown complete resolution of diastasis measured at rest; physiotherapy achieves a limited reduction in IRD during contraction, whose impact on satisfaction, appearance and function remains uncertain ³⁹. The meta-analysis of 16 trials (698 women) concludes that conservative interventions do not produce a clinically significant reduction in IRD, but that abdominal exercises may provide other physical and psychosocial benefits ⁴¹. And even when an anatomical gain is obtained (−8,05 mm), it does not translate into superior functional recovery on the ODI (MD 0,82; 95 % CI −2,75 to 4,38; p = 0,75) ³⁸.

Message 5: “What you are feeling is documented”

In 460 primiparous women at 6–8 months postnatally, 73,3 % reported having worried during pregnancy about the appearance of their abdomen, the mean degree of concern about their current appearance was 5,5/10 (SD 2,4), and nearly 80 % felt their abdominal muscles were weaker than before pregnancy; women reporting a midline protrusion (20,9 %) described themselves as weakened significantly more often ³¹. Vicente-Campos' mixed-methods study ³⁰ describes an emotional impact with feelings of abandonment by health institutions, shame, sadness, helplessness, lack of self-esteem, resignation and social pressure. Severe diastasis significantly affects quality of life (HerQLes) at birth (p = 0,001) and at 3–6 months (p = 0,01), with no effect on pelvic floor symptoms measured with the FPFQ ¹⁷.

4. What goes into the session

The crunch is not the enemy

This is probably the most counter-intuitive point in the file. A methodologically high-quality randomised trial (PEDro 8/10) in women with diastasis at 6–12 months postnatally shows that a 12-week home programme containing curl-ups neither worsened nor improved the IRD (mean difference 1 mm at rest 2 cm above the umbilicus, 95 % CI −1 to 4), while increasing the strength and thickness of the abdominal muscles ³². The classic contraindication to the crunch in moderate diastasis is therefore to be put into perspective.

Exercises do not all pull in the same direction

In 38 primiparous women, the IRD above the umbilicus was significantly reduced during a crunch, whereas the IRD below the umbilicus was significantly wider during an abdominal drawing-in exercise (drawing-in / transversus) than at rest ²⁴. In pregnant women with a diastasis ≥ 2,8 cm, the acute effects are quantified ³⁵ :

But “smaller IRD” ≠ “better”

This is the argument that stops the table above from being turned into a protocol. In women with diastasis, the automatic curl-up narrows the IRD but distorts the linea alba more, whereas pre-activation of the transversus reduces the IRD less while distorting the linea alba less; the authors stress that this smaller narrowing by the transversus, advised against until now, could on the contrary favour abdominal mechanics through tension transfer ²⁵. Anatomy supports this reading: the transverse fibres of the linea alba resist intra-abdominal pressure, whereas the oblique fibres are mainly loaded during trunk movements ¹⁸: transversus and obliques are not interchangeable synergists. And the linea alba is an anisotropic tissue: its Young's modulus is about 50 kPa transversely against 20 kPa longitudinally under physiological pressure (~20 kPa), a compliance ratio of roughly 2:1 ²⁰.

The most profitable parameter: timing

Structured programmes started before 3 months postnatally achieve a greater IRD reduction (−10,2 mm; 95 % CI −14,94 to −5,46) than late starts, with no significant difference between types of training (p = 0,32) ³⁸. In other words: when you start weighs more than what you choose. One format tested in 37 sportswomen: 3 weekly sessions, 1 supervised + 2 at home, started at around 3 months postnatally ³³.

And during pregnancy?

A preventive signal exists antenatally, a 35 % reduction in the presence of diastasis (RR 0,65; 95 % CI 0,46–0,92), but the authors conclude that non-specific exercise “may or may not” help, because of the poor methodological quality ⁴⁰. Low-quality evidence Theodorsen's randomised trial ³⁴ in 96 pregnant women at least settles the question of safety: the effect of a 12-week programme of abdominal and pelvic floor exercises was 2 mm (95 % CI −2 to 7), negligible both at the end of the intervention and at 6 weeks postnatally. Neither a demonstrated benefit nor any worsening: pregnant women can be left to train.

5. Common mistakes

Mistake no. 1: Measuring at the umbilicus, with the fingers, and tracking progress with that

That combines the two least reliable methods: inter-rater agreement of 63 % for the fingers ⁶, and an ICC that collapses to 0,63 at the umbilical level on head lift ⁷. An “improvement” measured that way may be nothing but noise.

Mistake no. 2: Crediting your protocol with your protocol's results

Skoura's scoping review ³⁶ stresses that most studies included women within the first 6 months postnatally, a period during which the spontaneous reduction in IRD may be confounded with the effect of the intervention. Prevalence goes from 100 % at the end of pregnancy to 39 % at 6 months with no intervention ²⁴. A “fine result” at 6 weeks–6 months is partly natural history: this applies to reading trials just as much as to appraising your own practice.

Mistake no. 3: Banning exercises

Of 1 000 Instagram posts screened, 28 were included: 61 % offered recommendations that were not evidence-based and only 7,1 % cited a scientific source, quality being rated poor (QUEST tool). The prescriptive “do / do not” lists were ubiquitous, and the women interviewed reported confusion, misinformation and nocebo effects ; recommendations consistent with the literature influenced only 20 % of them positively ³⁷. Reproducing that list in the clinic means importing the problem.

Mistake no. 4: Discouraging a return to activity

In a prospective cohort of 504 women followed from 3 to 12 months postnatally (diastasis measured with callipers), the sensation of vaginal heaviness and the diastasis decreased in every group, including in the high-impact women. Conversely, non-exercisers reported more severe pelvic girdle pain, had a weaker pelvic floor, and their stress urinary incontinence increased while it remained stable or improved in the active women ¹⁰. The authors explicitly invite physiotherapists to encourage an early return to low impact.

Mistake no. 5: Getting the risk factors wrong

The “obvious” factors do not always hold. At 6 months postnatally, no significant difference in pre-pregnancy BMI, gestational weight gain, birth weight or abdominal circumference between women with and without diastasis ²⁴ ; in He's final model ¹⁴, fetal weight, pre-pregnancy BMI and postnatal BMI were not significant (p > 0,05) whereas maternal age (OR 1,10 per year; 95 % CI 1,04–1,16) and the number of births (OR 2,09; 95 % CI 1,30–3,37) were. Cavalli's review ¹⁶ retains parity, BMI and diabetes as the most plausible, notes that caesarean section appears to be a risk factor only in women who have given birth twice, and reports contradictory results for age. On mode of birth, the data partly converge: vaginal birth associated with a reduced risk (OR 0,45; 95 % CI 0,40–0,51) ¹⁵, caesarean section an independent risk factor (OR 2,297; 95 % CI 1,327–3,978; p = 0,003) ¹³, and a factor for persistence (p = 0,05) ¹⁷. In the long term, BMI, parity, twin pregnancies and diabetes come out depending on the postnatal time point ³.

Mistake no. 6: Promising anatomy

Diastasis is not just a reversible mechanical distension. Type I and type III collagen are significantly less abundant in the midline fascia of women with diastasis (p < 0,001; ex. collagène I sus-ombilical 244,5 ± 73,5 vs 381,1 ± 101,1 kpixels) ²³. ShearWave elastography shows a wall that is reorganised and not merely stretched: stiffness lowered in the rectus abdominis (p = 0,003) and the external oblique (1,65 ± 0,15 vs 1,79 ± 0,14, p = 0,001), but increased in the transversus (p < 0,001), avec un écartement maximal siégeant au niveau de l'ombilic (4,59 ± 1,14 cm) ²⁷.

6. When to refer on, and to whom

Referral without delay (before any conservative trial)

A painful or irreducible midline bulge, or any suspicion of an associated umbilical or epigastric hernia. The comorbidity is frequent: in 1 294 cases of diastasis, 35,8 % of the women had one or more hernias (p < 0,001 vs hommes), la hernie ombilicale étant le type le plus important; chez les femmes, l'âge (OR 1,51; IC 95 % 1,33–1,72; p = 0,000) et le tabagisme (OR 1,66; IC 95 % 1,13–2,44; p = 0,010) étaient des facteurs de risque de hernie associée ⁴. The stakes are surgical, not rehabilitative: in 231 patients operated on for a small umbilical or epigastric hernia (< 2 cm) par simple suture sans filet, la récidive a été de 31,2 % (29/93) with an associated diastasis against 8,3 % (9/108) without (p < 0.001), with the authors strongly recommending that a diastasis be looked for before surgery ⁵. In Vita's series of sportswomen ³³, 6 patients out of 37 were referred for surgery: 2 for hernia, 4 for a diastasis > 4 cm.

Referral after a conservative trial

Physiotherapy is the first therapeutic tier for symptomatic diastasis; surgery comes only second-line. If the patient comes back after 2 to 6 months of conservative treatment with persistent symptoms, referral to a surgeon may be considered, and, where possible, surgery should wait until at least 1 year postnatally, since some patients experience spontaneous resolution during the first year ⁴³.

Which profile benefits?

The documented subgroup is not “the largest IRD”, it is the training-resistant diastasis. In the only randomised trial comparing surgery with training (86 patients: 29 retromuscular mesh, 27 double-row plication, 32 on a 3-month programme), a significant muscle gain was achieved in every group, training included, but the perceived strength gain was significantly greater in the two operated groups, and the patients in the training group continued to have bodily pain at follow-up ⁴⁵. Olsson's cohort ⁴⁶ concerns precisely 60 postnatal women with diastasis and “training-resistant canister dysfunctions”, operated on by plication: at 3 years, every parameter of the Disability Rating Index was improved (p < 0,001), avec gain de force et stabilité du caisson (p < 0,001), force des muscles du dos (p < 0,001) et des abdominaux (p = 0,002), et amélioration de l'incontinence urinaire (UDI-6 p < 0,001; IIQ-7 p = 0,004), stable entre 1 et 3 ans.

What must be said honestly before referring

• There is no surgical consensus on the repair indications or on the optimal technique (PRISMA review, 37 studies, 45 techniques); no significant difference in complications (p = 0,165) or recurrences (p = 0,133) between open and laparoscopic approaches after adjustment for concomitant hernia repair; double-layer suture closure is associated with a significantly lower complication rate (p = 0,002) ⁴⁷.
• The figures to give : in 931 operated patients (18–70 years, follow-up from 3 weeks to 20 years), recurrence 5 %, seroma 7 %, abdominal hypoaesthesia 6 %, surgical site infection 2 %, chronic pain 4 %; satisfaction high overall but assessed subjectively in the majority ⁴⁸.
• Plication during an abdominoplasty : in 497 patients (mean age 44,5 years, 94,4 % women), improvement in the SF-36 physical function subscale in the 4 studies that used it, but only 2 studies out of the 3 measuring abdominal strength show a significant improvement; complications 17,0 % ⁴⁹. The strength improvements are less consistent than the functional results.

A special case: the sportswoman

The classic rehabilitation reference points are widely overtaken by real-world practice: in 34 Norwegian elite athletes and 34 active controls, the majority of the athletes and one control in three returned to sport or exercise between 0 and 6 weeks postnatally; four athletes had stress fractures postnatally, and the athletes described themselves as dissatisfied with the advice received on strength training and nutrition during pregnancy ⁴⁴. The operational message is less “slow down” than “support them, or they will go back without you”.