The influence of the delivery route on pelvic floor muscle strength

Purpose: to evaluate the influence of the delivery route on pelvic floor (PF) muscle strength. Methods: a cross-sectional study was conducted to evaluate PF muscle strength by the pelvic floor strength evaluation (PFSE) test and perineometer in primiparous patients aged 20 to 30 years 4 to 6 months after delivery. The categorization was: zero – lack of muscle contraction; one – weak contraction; two – moderate contraction not sustained for 6 s and three – normal contraction sustained for 6 s. A total of 94 patients were divided into there groups based on prior delivery route. They were: 32 patients with vaginal delivery with singleton cephalic presentation; 32 patients with cesarean delivery, and 30 nulliparous patients as a control group. The independent variable was delivery route and the dependent one was the muscle strength of the PF. Comparison between contraction levels was performed by Kruskal-Wallis and Dunn multiple comparison tests and the influence of delivery method was tested by χ 2 . Confidence interval of 95% was obtained for relative risk (RR) of PF muscle strength changes and kappa statistics. Results: the 1st and 3rd quartiles of delivery route regarding PF muscle strength were lower (p=0.01) for vaginal delivery (2.0;1-2) and intermediate for cesarean section (2.0;2-3) compared to the nulliparous (3.0;2-3) by the PFSE test and perineometer. RR of the altered examination was increased after vaginal delivery (RR=2.58; CI 95%: 1.32-5.04, p=0.002); (RR=2.31; CI 95%: 1.24-4.32, p=0.005), and after cesarean section (RR=1.56; CI 95%: 0.94-2.57, p= 0.12); (RR=1.38; CI 95%: 0.85-2.23, p=0.29) by AFA and perineometer, respectively. Conclusions: vaginal delivery decreased PF muscle strength when compared with cesarean delivery and control groups.