Flatus and faecal incontinence: prevalence and risk factors at 16 weeks ofgestation

Objective To evaluate the prevalence of anal incontinence at 16 weeks of ge station and to identify possible maternal and obstetrical risk factors. Design Cross sectional study and cohort study. Setting Department of Obstetrics and Gynaecology, Aarhus University Hospita l, Denmark. Participants Cross sectional study: 7557 women attending antenatal care. Co hort study: a subgroup of 1726 pregnant women with one previous delivery at our department. Results The prevalence of anal incontinence within the preceding year was 8 6%. Incontinence of liquid and solid stools was reported in 2.3% and 0.6%, respectively. Isolated flatus incontinence at least once a week was reporte d in 4.2%. The risk of flatus incontinence at least once a week was increas ed with age > 35 years (OR 1.6; 95% CI 1.1-2.4) and with previous lower abd ominal or urological surgery (OR 1.5, 95% CI 1.1-2.1) in a logistic regress ion model controlling for maternal factors. Increasing parity did not incre ase the risk. The risk of flatus incontinence was increased after anal sphi ncter tear and birthweight > 4000 g in a logistic regression model controll ing for maternal and obstetric variables. Episiotomy was insignificantly as sociated, while spontaneous perineal tear > 3 cm and a number of other intr apartum factors were not associated. Conclusion True faecal incontinence is rare among younger women. However, a n age > 35 years and previous lower abdominal or urological surgery increas ed the risk of flatus incontinence in contrast to increasing parity. This s uggests that childbirth plays a minor role compared with age. However, when analysing obstetric variables separately, a birthweight > 4000 g, and anal sphincter tears were significant risk factors for natus incontinence.