Anal incontinence after childbirth

Incontinence of stool and flatus are frequent complications of childbirth. We examined the prevalence and possible causes of these adverse outcomes in a large cohort of women.

We studied 949 pregnant women who gave birth in 5 hospitals in 1995/96 in the province of Quebec. These women, participants in a randomized controlled trial of prenatal perineal massage, completed a self-administered questionnaire 3 months after giving birth.

Three months after delivery 29 women (3.1%) reported incontinence of stool, and 242 (25.5%) had involuntary escape of flatus. Incontinence of stool was more frequent among women who delivered vaginally and had third- or fourth-degree perineal tears than among those who delivered vaginally and had no anal sphincter tears (7.8% v. 2.9%). Forceps delivery (adjusted risk ratio [RR] 1.45, 95% confidence interval [CI] 1.01-2.08) and anal sphincter tears (adjusted RR 2.09, 95% CI 1.40-3.13) were independent risk factors for incontinence of flatus or stool or both. Anal sphincter injury was strongly and independently associated with first vaginal birth (RR 39.2, 95% CI 5.4-282.5), median episiotomy (adjusted RR 9.6, 95% CI 3.2-28.5), forceps delivery (adjusted RR 12.3, 95% CI 3.0-50.4) and vacuum-assisted delivery (adjusted RR 7.4, 95% CI 1.9-28.5) but not with birth weight (adjusted RR for nirth weight 4000 g or more: 1.4, 95% CI 0.6-3.0) or length of the second stage of labour (adjusted RR for second stage 1.5 hours or longer compared with less than 0.5 hours: 1.2, 95% CI 0.5-2.7).

Anal incontinence is associated with forceps delivery and anal sphincter laceration. Anal sphincter laceration is strongly predicted by first vaginal birth, median episiotomy, and forceps or vacuum delivery but not by birth weight or length of the second stage of labour.