The study was done to explore changes in the prevalence of AI from late first pregnancy to 6 years postpartum and to evaluate possible risk factors for changes in AI during the 6‐year period. The research design that was selected was a Prospective longitudinal cohort study in two Norwegian health regions.

The participants in the study were the women with first deliveries between May 2009 and December 2010. Participants reported AI in late pregnancy, 6 months, 1, and 6 years after first delivery using postal or digital questionnaires. AI prevalence was calculated, and mixed-effects Poisson regression analyses with robust variance were applied.

In the total 1571 participants, 65% had normal vaginal first deliveries, 20% had vaginal deliveries complicated by instrumental intervention, and/or obstetric anal sphincter injury. Nearly 1 in 10 women reported persistent incontinence during the 6 years. Moreover, women who were <23 years, ≥34 years, unemployed during the first pregnancy, who had active bowel disease, or bowel evacuation problems during the 6‐year period had higher AI prevalence.

The study concluded that complicated vaginal delivery, age, and bowel emptying problems increase the risk of long‐term anal incontinence.