Title: Risk factors of pelvic floor muscle strength in south Chinese women: a retrospective study
Abstract: Abstract Objectives: To to evaluate pelvic floor muscle strength using surface electromyography and risk factors of pelvic floor muscle strength in early postpartum period. Methods: This retrospective study included 21302 participants who visited Fujian Maternity and Child Health Hospital from September 2019 to February 2022. All participants were assessed by medical professionals for general information and surface electromyography. Results: Age and neonatal weight showed a negative linear relation with rapid, tonic and endurance contraction (β=-.298, P <0.001; β=-.354, P <0.001; β=-.310, P <0.001, respectively; β=-1.199, P <0.001; β=-.380, P <0.05; β=-.436, P <0.01, respectively). Secundipara had a positive effect on rapid, tonic, and endurance contraction than primipara (β=-.055, P <0.001; β=-.032, P <0.001; β=-.029, P <0.001, respectively). All factors showed even positive values in tertipara (β=-.025, P <0.001; β=-.018, P =0.010; β=-.021, P =0.002, respectively). Contrarily, body mass index, education and Gestational weight gain (endurance contraction only) also showed a positive linear relation with three types of contraction (β=.546, P <0.001; β=.366, P <0.001; β=.309, P <0.001, respectively; β=2.767, P <0.001; β=3.141, P <0.001; β=2.391, P <0.001, respectively; β=0.046, P <0.01). Participants with caesarean section had a positive effect on rapid, tonic, and endurance contraction than participants with non-instrumental vaginal delivery (β=-.292, P <0.001; β=-.305, P <0.001; β=-.324, P <0.001, respectively); episiotomy (β=-.216, P <0.001; β=-.224, P <0.001; β=-.239, P <0.001, respectively); and forceps delivery (β=-.176, P <0.001; β=-.182, P <0.001; β=-.185, P <0.001, respectively). Conclusions: We found that age, neonatal weight, vaginal delivery, episiotomy, and forceps were risk factors of pelvic floor muscle strength; oppositely, body mass index, parity (≤3) and gestational weight gain had a positive relation with pelvic floor muscle strength.