Anal sphincter damage after vaginal delivery: functional outcome and risk factors for fecal incontinence

OBJECTIVE: To assess the role of anal sphincter damage following delivery in the development of anorectal complaints and urinary incontinence, and to identify obstetric factors associated with subsequent fecal incontinence. METHODS: The retrospective cohort study with matched controls used a postal questionnaire and analysis of delivery and operation records from all women who underwent primary repair of a third or fourth degree perineal rupture in our hospital between 1971 and 1991, and their controls, matched for date and parity. Frequencies of complaints were compared using the Mantel-Haenszel common odds ratio OR] for matched-control studies. Obstetric risk factors for fecal incontinence were assessed with multivariate logistic regression analysis. RESULTS: In the period studied, 171 women underwent a primary repair. One hundred and forty-seven of which returned the questionnaire (86%), compared with 131 of the controls (73%). Analysis was performed on 125 matched pairs with a median follow-up of 14 years. Fecal incontinence was reported by 39 patients and 16 controls (OR: 3.09; 95% confidence interval: 1.57-6.10). Urinary incontinence was reported by 65 cases and 52 controls (OR:1.46; 95% CI: 0.91-2.37). Among women with anal sphincter damage, the extent of anal sphincter damage was an independent risk factor for fecal incontinence. (OR: 2.54; 95% CI: 1.45-4.45). Subsequent vaginal delivery was not associated with the development of fecal incontinence (OR: 2.32; 95% CI: 0.85-6.33). In primiparous women mediolateral episiotomy protected for fecal incontinence after anal sphincter damage (OR: 0.17; 95% CI: 0.05-0.60). CONCLUSIONS: Anal sphincter damage following delivery is significantly associated with subsequent anorectal complaints, but not with urinary incontinence. The extent of sphincter damage is an independent risk factor for the development of fecal incontinence. Mediolateral episiotomy protects for fecal incontinence in primiparous women.