• Anal incontinence;
  • post partum ;
  • predictors;
  • pregnancy;
  • prevalence


To evaluate the prevalence and predictors of anal incontinence (AI) in late pregnancy and 1 year after delivery.


Prospective population-based cohort study.


Two maternity units in Norway 2009–2010.


Primiparae aged 18 years or over.


Primiparae answered questions on the St. Mark's score about AI during the last 4 weeks of pregnancy. One year later, the same questionnaires were distributed by postal mail. Socio-economic and delivery-related data were obtained from hospital records.

Main outcome measures

Self-reported AI.


Answers on AI in late pregnancy were obtained from 1571 women, and 1030 responded 1 year later. Twenty-four per cent experienced one and 4.7% experienced three or more AI symptoms in late pregnancy. One year later, this was reduced to 19% and 2.2%, respectively. Multivariate logistic regression analyses were applied. Formed and loose stool incontinence were strongly associated at both time points. The main predictor of AI 1 year after delivery was AI in late pregnancy. Obstetric anal sphincter injury increased the risk of incontinence of stool and flatus (odds ratio [OR], 4.1; 95% confidence interval [CI], 1.7–9.6) after delivery. Urgency was associated with greater age (OR, 1.8; 95% CI, 1.0–3.3) and operative delivery (OR, 2.0; 95% CI, 1.3–2.9).


One in four primiparae experienced AI in late pregnancy. One year later, still one in five suffered from incontinence. Sphincter injury predicted incontinence of stool and flatus, whereas greater age and operative delivery predicted urgency. The identification and adequate follow-up of pregnant women with AI may reduce AI after delivery.