Effects of Different Indications for Forceps Delivery on Pelvic Floor Muscle Surface Electromyography and Early Postpartum Pelvic Floor Function in Primiparas

Background: Forceps-assisted vaginal delivery is closely associated with postpartum pelvic floor muscle (PFM) injury and postpartum pelvic floor dysfunction. The present study utilized Glazer PFM surface electromyography (sEMG) and International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI-SF) for the objective assessment of postpartum PFM function to determine the effects of different forceps delivery indications on early postpartum pelvic floor function in primiparas. Methods: Four hundred primiparas whose pregnancies had been terminated by forceps delivery were divided into three groups based on the indication for forceps delivery: fetal distress (FD) (n = 260), prolonged second stage of labor (PSSL) (n = 30), and intrapartum fever combined with fetal distress (IFFD) (n = 110). Pelvic floor muscle surface electromyography (EMG) performed according to the Glazer protocol at 42-60 days postpartum was the primary outcome measure. Results: The overall Glazer assessment scores of the PSSL (54.4 +/- 18.6) and IFFD (54.6 +/- 15.8) groups were significantly lower than that of the FD group (59.3 +/- 17.0) (p = 0.019). The peak EMG value during the fast-twitch stage for the FD, PSSL, and IFFD groups was 32.4 +/- 17.7, 31.7 +/- 26.1, and 26.5 +/- 12.2 mu V, respectively; the IFFD and FD groups were significantly different (p < 0.05). The incidence of postpartum stress urinary incontinence (SUI) was significantly higher in the IFFD and PSSL groups; the IFFD and FD groups were significantly different (p < 0.05). Conclusions: Intrapartum fever probably affects the early postpartum pelvic floor function of primiparas who underwent forceps delivery, which mainly manifests in the short term as reduced fast-twitch muscle strength and SUI.