Effect of prolonged second stage of labor on pelvic floor function: A prospective cohort study.

ABSTRACT

INTRODUCTION AND HYPOTHESIS: To evaluate the effect of the second stage of labor (SSL) lasting > 2 h on pelvic floor function. METHODS: This single-center prospective cohort study included primiparous women with SSL > 2 h treated at Tongji Hospital between January 2018 and December 2019 (case group). A matched group of women with similar newborn weight and SSL < 2 h were recruited simultaneously (control group). Stress urinary incontinence (SUI) and pelvic floor muscle (PFM) characteristics were measured at 6 weeks, 6 months, and finally 1 year postpartum. RESULTS: A total of 63 pairs of primiparous women completed 1-year follow-up. The incidence of SUI in the case group was significantly higher than that in the control group at 6 weeks postpartum (P = 0.020); however, the differences were not significant at 1 year postpartum (P=1.00). PFM endurance was significantly lower in the case group at 6 weeks (P = 0.000), 6 months (P = 0.000), and 1 year (P = 0.011) after childbirth. There was no difference in PFM strength between the two groups. The maximal voluntary contraction (MVC) of PFM was significantly lower in the case group at 6 weeks postpartum (P = 0.007), but the differences were not significant at 1 year postpartum (P = 0.197). PFM endurance and MVC were higher at 1 year than at 6 weeks postpartum in both groups. CONCLUSIONS: The SSL > 2 h increased the incidence of SUI at 6 weeks postpartum and decreased PFM endurance for 1 year.