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

OBJECTIVE

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.

DESIGN

Longitudinal cohort study.

SETTING

Akershus University Hospital, Norway.

SAMPLE: 880 women with vaginal births.

METHODS

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.

MAIN OUTCOME MEASURES: Bothersome vaginal flatus, defined as responding "often" or "always" to the question "Are you bothered by sounds caused by air escaping from the vagina?"

RESULTS

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).

CONCLUSION

Parity and differences in pelvic floor anatomy affect the odds for bothersome vaginal flatus during the first postpartum year.