RESUMO
OBJECTIVE: To assess the link between mediolateral episiotomy and the occurrence of obstetrical anal sphincter injury (OASIS). METHODS: Data were collected from the national database (PMSI; Programme de Médicalisation des Systèmes d'Information). Women between 18 and 50 years old, undergoing a vaginal delivery in France in 2018 were included. The main outcome was factors associated with a higher adjusted OASIS rate after a vaginal delivery. RESULTS: Of 623 003 women with a vaginal delivery, 239 949 were primiparous (38.5%), 62 310 experienced mediolateral episiotomy (10.0%) and 7077 had a third- or fourth-degree perineal tear (1.14%). Risk factors for OASIS were primiparity (adjusted odds ratio [OR] 2.97), shoulder dystocia (aOR 2.57), instrumental delivery (aOR 2.81), gestational diabetes (aOR 1.20), and post-term delivery (aOR 1.53). Mediolateral episiotomy increased the occurrence of OASIS for women without an instrumental delivery, either for parous (OR 1.32, 95% confidence interval [CI] 1.07-1.62) or primiparous (OR 1.26, 95% CI 1.13-1.39) women. In contrast, episiotomy among primiparous women with episiotomy and a vacuum or forceps delivery significantly decreased the risk for OASIS (OR 0.62, 95% CI 0.56-0.67). CONCLUSIONS: The practice of routine episiotomy should be discouraged. Selective mediolateral episiotomy should be considered with extreme caution and mainly for primiparous women during instrumental vaginal delivery. Further randomized trial may confirm such results.
