Anal incontinence in women with recurrent obstetric anal sphincter rupture: a case control study

To determine the risk of recurrent anal sphincter rupture (ASR), and compare the risk of anal incontinence (AI) after recurrent ASR, with that seen in women with previous ASR who deliver by caesarean section or vaginally without sustaining a recurrent ASR.

Women with recurrent ASR between January 2000 and June 2011 were identified at two delivery wards in Copenhagen. The women answered a questionnaire with a validated scoring system for AI (St. Mark`s score), and the results were compared with those obtained in two control groups: women with subsequent uncomplicated vaginal delivery or caesarean section.

There were 93 437 vaginal deliveries. ASR occurred in 5.5% (n = 2851) of the nulliparous and 1.5% (n = 608) of the multiparous women. Recurrent ASR occurred in 8% (n = 49) of whom 50% reported symptoms of AI. We found no difference in the occurrence of AI between women with recurrent ASR, and those who delivered vaginally without repeat ASR (p = 0.37; OR = 2.0) or by caesarean section (p = 0.77; OR = 1.3).

Women with a past history of ASR have an 8% risk of recurrence. AI affects half of the women with recurrent ASR. Larger studies are required to confirm our findings.