Prevalence and Risk Factors for Vaginal Flatus From Mid-Pregnancy to 12 Months Postpartum: A Longitudinal Cohort Study.

Abstract

To assess the prevalence of and trend in bothersome vaginal flatus from mid-pregnancy to 12 months postpartum, according to vaginal parity. The secondary objective was to assess differences in pelvic floor anatomy as risk factors for bothersome flatus at 12 months postpartum. Longitudinal cohort study. Akershus University Hospital, Norway. 880 women with vaginal births. Participants completed questionnaires in mid-pregnancy, at 3 and 12 months postpartum, and attended a gynaecological examination including ultrasound at 12 months postpartum. Parity was classified as primipara, secundipara, or multipara (no, one, or ≥ 2 previous vaginal births, respectively). A generalised linear mixed model and logistic regression models were used for analysis. Bothersome vaginal flatus, defined as responding "often" or "always" to the question "Are you bothered by sounds caused by air escaping from the vagina?" The prevalence of bothersome flatus in mid-pregnancy, at 3 and 12 months postpartum was: primiparas: 0.7%, 4.0%, and 2.5%; secundiparas: 2.3%, 4.4%, and 7.3%; multiparas: 5.4%, 3.0%, and 7.1%, respectively. Compared to primiparas, multiparas had higher odds in pregnancy (OR 14.0, 95% CI 1.8-108.1), and both secundi- and multiparas had higher odds at 12 months postpartum (OR 4.8, 95% CI 1.3-17.6, and OR 6.4, 95% CI 1.1-38.6, respectively). Independent risk factors for bothersome flatus included levator avulsion (aOR 3.6, 95% CI 1.5-8.7), a larger genital hiatus (aOR 2.0, 95% CI 1.2-3.3), and a shorter perineal body (aOR 0.8, 95% CI 0.6-1.0). Parity and differences in pelvic floor anatomy affect the odds for bothersome vaginal flatus during the first postpartum year.