Intended for healthcare professionals

Clinical Review

Obstetric anal sphincter injury

BMJ 2010; 341 doi: (Published 09 July 2010) Cite this as: BMJ 2010;341:c3414

This article has a correction. Please see:

  1. Danielle Abbott, specialty trainee year 2 in obstetrics and gynaecology1,
  2. Natalie Atere-Roberts, specialty trainee year 2 in obstetrics and gynaecology2,
  3. Andrew Williams, consultant colorectal surgeon and honorary senior lecturer1,
  4. Eugene Oteng-Ntim, consultant obstetrician and honorary senior lecturer1,
  5. Lucy C Chappell, senior lecturer in maternal and fetal medicine3
  1. 1Guy’s and St Thomas’ NHS Foundation Trust, London SE1 7EH
  2. 2Oxford Radcliffe Hospitals NHS Trust, Headington, Oxford OX3 9DU
  3. 3King’s College London, London SE1 7EH
  1. Correspondence to: L Chappell lucy.chappell{at}
  • Accepted 16 June 2010

Summary points

  • Obstetric anal sphincter injury affects about 2.9% of primiparous women who deliver vaginally

  • Of women who have sustained such an injury, 60-80% are asymptomatic at 12 months, of whom most report incontinence of flatus only

  • Most women with faecal incontinence will not volunteer this information unless asked, so midwives, health visitors, obstetricians, and general practitioners should be aware of the problem and take a careful history

  • Affected women should be referred to a perineal clinic for further investigation with endoanal ultrasonography and manometry

Anal sphincter injury during childbirth is a leading cause of anal incontinence. In a study of more than 20 000 consecutive vaginal deliveries, clinically diagnosed obstetric anal sphincter injury occurred in 2.9% of primiparous women and 0.8% of multiparous ones.1 Of women who have sustained such an injury, 60-80% are asymptomatic at 12 months, of whom most report incontinence of flatus only, rather than faeces.2 w1 w2 Establishing a correct diagnosis at time of injury will facilitate adequate repair and may prevent future incontinence.3 In one epidemiological study, only a third of people with faecal incontinence had ever discussed the problem with a doctor because of embarrassment or fear of stigma.4 This review outlines the determinants, diagnosis, and management of obstetric anal sphincter injury. Women affected by obstetric anal sphincter injury require acute management at the time of delivery, together with follow-up or referral when newly presenting with symptoms months or years after childbirth. This review is relevant to all who provide care during childbirth and to doctors and healthcare professionals to whom women may subsequently present.

Sources and selection criteria

We searched Medline and PubMed from 1980 to 2009, focusing on evidence based publications on obstetric anal sphincter injury and randomised trials for management of such injury. We supplemented these sources with selected systematic reviews and good …

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