Electromyographic activity of the pelvic floor muscles in the third trimester: comparison between primigravidae and secundigravidae

Objective: The objective was to compare the electromyographic activity of pelvic floor muscle (PFM) on third semester between primigravidae and secundigravidae who had previous vaginal delivery. Design: Cross-sectional observational study. Sample: Nineteen primigravidae and 21 secundigravidae between 34th and 36th gestational weeks were evaluated, Materials and Methods: Data collection consisted in assessing the PFMs activity by surface electromyography. Main outcome measures: The variables related to electromyographic assessment such peak and average on the rest, maximal voluntary contraction, and sustained contraction. Results: There were 110 differences on electromyographic activity of PFMs between primigravidae and secondigravidae. However, a significant increase in body mass index and a negative correlation of the newborn weight with the peak value of electromyographic signal during maximal voluntary contraction were observed. Conclusions: The factors that can change the electromyographic activity pattern during pregnancy can he related to maternal body mass increased and newborn weight.