Aims: Damage to the anal sphincter has been considered as the cause of anal incontinence after childbirth. The aims of the present study were to determine prospectively the incidence of anal incontinence and anal sphincter damage after childbirth, and their relationship with obstetric parameters in France.
Patients and methods: We studied 259 consecutive women six weeks before and eight weeks after delivery. They were asked to fill out a questionnaire dealing with faecal and urinary incontinence. Anal endosonography (B&K 7-10 MHz) was then performed. Two independent observers analyzed internal and external anal sphincters.
Results: Two hundred and thirty-three women (90%) were assessed, among whom 31 had had a caesarean section. De novo sphincter defects were observed in 19.3% (39 patients) in the postpartum period only after vaginal delivery (202 patients). These disruptions occurred with the same incidence after the first and second childbirth. Independent risk factors (odds ratio; 95% confidence interval) for sphincter defect were forceps (odds ratio 11.9; 4.8-33.3), perineal tears (odds ratio 16.1; 4.4-83.9), episiotomy (odds ratio 6.6; 1.7-34.2), and pauciparity < or = 2 (odds ratio 8.8; 1-78.3), as revealed by multivariate analyses. The overall rate of de novo anal incontinence was 9% (20 patients), and independent risk factors involved forceps (odds ratio 4.5; 1.5-13), perineal tears (odds ratio 3.9; 1.4-10.9), de novo sphincter defect (odds ratio 5.5; 5-15) and prolonged labor (odds ratio 3.4; 1-11). Among the 20 women who had de novo anal incontinence, only 45% (9 patients) had sphincter defects.
Conclusion: De novo anal incontinence after delivery is multifactorial and anal sphincter defects account only for 50% of them. Primiparous and secundiparous women have the same high-risk factor for sphincter disruption and anal incontinence. Since external anal sphincter disruptions are more frequent than internal anal sphincter damage, surgical repair should be discussed.