Obstetric anal sphincter injuries—Maternal, fetal and sociodemographic risk factors : A retrospective register-based study
Introduction: Obstetric anal sphincter injuries (OASIS) are severe complications to vaginal births with potentially serious long-term consequences and large impact on quality of life. The aim was to determine risk and protective factors for OASIS. Material and methods: We performed a retrospective register-based observational study. A cohort of 988 988 singleton term deliveries 2005–2016 in Sweden