Pelvic floor muscle function before and after first childbirth

Abstract

Introduction and hypothesis: Pregnancy and vaginal delivery are considered to be the main risk factors for development of pelvic floor dysfunction. We hypothesize that; 1) pelvic floor muscle (PFM) strength and endurance is significantly reduced by first delivery in general, and 2) changes in PFM strength and endurance are influenced by mode of delivery.

Methods: Prospective repeated measures observational study. Thirty-six women completed the study. PFM function was measured as vaginal squeeze pressure. Paired t-test was used to compare PFM function before and after first childbirth for all participants as a group. One-way ANOVA was used to compare changes between different modes of delivery.

Results: A significant reduction in PFM strength (p < 0.0001) and endurance (p < 0.0001) was found for all participants after first childbirth. The reduction in strength was 20.1 hPa (CI:16.2; 24.1), 31.4 hPa (CI: 7.4; 55.2) 5.2 hPa (CI: -6.6; 17.0) in the normal vaginal, instrumental vaginal and acute cesarean groups, respectively. The difference was significant between normal vaginal and acute cesarean birth (p = 0.028) and instrumental vaginal and acute cesarean birth (p = 0.003).

Conclusion: PFM strength is significantly reduced after vaginal delivery, both normal and instrumental, 6 to 12 weeks postpartum. Acute cesarean section resulted in significantly less muscle strength reduction.