Eight studies (four case studies, one quasi-experimental post-test studies, two retrospective observational studies and one randomised controlled trial) were included in the review (336 participants). Seven out of eight studies were rated as fair to poor in quality (scores ranged from 12 to 23 out of 28 points); overall quality was judged to be fair. There was a lack of blinding in all of the trials.
Antenatal exercise: Three studies reported that antenatal exercise reduced the presence of diastasis of the rectus abdominis muscle by 35% (RR 0.65, 95% CI 0.46 to 0.92; Ι²=39%; NNT=3) compared with non-exercising control groups. Two studies (one reported both antenatal and postnatal) showed that antenatal exercise reduced the width of diastasis during the antenatal and postnatal periods (no pooled analysis). No significant difference was found for the time to recovery of diastasis of the rectus abdominis muscle (one study).
Postnatal exercise: One RCT reported a reduction in diastasis of the rectus abdominis muscle width with postnatal abdominal exercise. Two studies reported a reduction in diastasis width with combined abdominal exercise and a tubigrip/corset and or posture/back care education (no pooled analysis).
One study reported the effects of diastasis of the rectus abdominis muscle on quality of life; aerobic exercise and neuromuscular education improved physical and social SF36 scores.
No adverse events were reported in any of the included studies.