Introduction and hypothesis: We compared the maximal voluntary contraction (MVC) and strength of pelvic floor muscles (PFM) of pregnant and nonpregnant women using surface electromyography (SEMG).
Methods: Fifteen pregnant primiparous women and 15 nulliparous nonpregnant women were evaluated. The healthy pregnant women were in the third trimester of pregnancy with a single fetus and did not have any neuromuscular alterations. The nonpregnant women did not present with PF dysfunctions and, as with the pregnant women, did not have any previous gynecological surgeries or degenerative neuromuscular alterations. The evaluation methods used were digital palpation (Oxford Grading Scale, which ranges from 0 to 5) and SEMG. In the EMG exam, MVC activity was evaluated, and the better of two contractions was chosen. Before the evaluation, all women received information about PFM localization and function and how to correctly contract PFM.
Results: In the EMG evaluation, MVC was significantly greater in the nonpregnant group (90.7 μv) than in the pregnant group (30 μv), with p < 0.001. The same results were observed after vaginal palpation, measured by the Oxford scale, which presented an average of 2.1 in the pregnant group and 4.5 in the nonpregnant group (p = 0.005).
Conclusion: In comparison to nulliparous women, pregnant women demonstrated worse PFM function with decreased strength and electrical activity.