The effect of episiotomy on pelvic floor muscle function within six months after first childbirth through electromyography and questionnaires assessment

Objective: To compare the impact of mediolateral episiotomy on pelvic floor muscle (PFM) function through surface electromyography (sEMG) and quality of life questionnaire assessment. Methods: From January 2018 to June 2019, 1 250 eligible primiparous women were enrolled in Beijing Hospital and the First People's Hospital of Yunnan Province. Participants were divided into episiotomy group (n=676)and non-episiotomy group (n=574). Both groups underwent clinical pelvic examination, sEMG assessment, and quality of life (QOL) questionnaire assessment at two fixed time points: 6-8 weeks, 6 months after vaginal delivery. Follow-up of sEMG amplitudes and their correlation with QOL questionnaire scores were evaluated. Results: Among the women delivered with episiotomy, the peak amplitude of phasic contraction (PPC) was (17.7±5.3) μV at 6-8 weeks after childbirth and (29.6±8.7) μV at 6 months after childbirth. The mean amplitude of tonic contraction (MTC) was (14.8±7.4) μV and (22.2±8.9) μV, respectively. In the non-episiotomy group, PPC was (20.0±7.9) μV and (35.4±10.7) μV at 6-8 weeks and 6 months, and MTC was (17.8±9.0) μV and (27.5±8.9) μV, respectively. Compared with EMG amplitudes at 6-8 weeks, both PPC and MTC significantly improved at 6 months in both groups (all P<0.01). Moreover, episiotomy was related with significantly lower PPC and MTC at both fixed checkups. Besides, both IIQ-7 and PFIQ-7 questionnaire scores improved at 6 months compared with those at 6-8 weeks in both groups (all P<0.001). There was consistently significant difference in QOL scores between episiotomy and non-episiotomy group at two checkups (all P<0.05). A negative correlation was observed between PFM contractile amplitudes and QOL scores at both time points after childbirth (all P<0.05), and the correlation weakened with time. Conclusion: Episiotomy has a negative impact on the postpartum PFM contractile function within 6 months after childbirth. The negative correlation between the sEMG and QOL scores indicates that sEMG is a candidate assessment for PFM function follow-up after childbirth.