Evolution and risk factors of anal incontinence during the first six years after first delivery: A prospective cohort study.

OBJECTIVE: To explore changes in prevalence of anal incontinence (AI) from late first pregnancy to six years postpartum, and to evaluate possible risk factors for changes in AI during the six-year period. DESIGN: Prospective longitudinal cohort study SETTING: Two Norwegian health regions POPULATION OR SAMPLE: Women with first deliveries between May 2009 and December 2010 METHODS: Participants reported AI in late pregnancy, six months, one and six years after first delivery using postal or digital questionnaires. AI prevalence was calculated, and mixed effects poisson regression analyses with robust variance were applied. MAIN OUTCOME MEASURES: AI from late pregnancy to six years postpartum RESULTS: Amongst 1571 participants, 65% had normal vaginal first deliveries, 20% had vaginal deliveries complicated by instrumental intervention and/ or obstetric anal sphincter injury (IVD±OASIS). Nearly one in ten women reported persistent incontinence during the six years. The overall AI prevalence was reduced from late pregnancy to one year postpartum for all modes of delivery. At six years postpartum, women with IVD±OASIS had a higher AI prevalence (23%; 95%CI:16%-30%) compared to women with caesarean section (8%;95%CI:2%-13%) or normal vaginal delivery (12%;95%CI:9%-16%). Moreover, women who were < 23 years, ≥34 years, unemployed during first pregnancy, had active bowel disease (PR:2.4;95%CI:2.0,2.7), or bowel evacuation problems during the six-year period had higher AI prevalence. CONCLUSIONS: Mode of first delivery modified AI prevalence during the six-year period, whereas age, bowel disease and bowel evacuation problems were associated with higher prevalence of AI from late first pregnancy to six years postpartum. FUNDING: This project was made possible by research grants awarded by the Department of Research at Ostfold Hospital Trust.