The optimal angle of the mediolateral episiotomy at crowning of the head during labor

Introduction and hypothesis The aim of the mediolateral episiotomy incision is to increase the diameter of the soft tissue of the vaginal outlet to facilitate birth and to prevent vaginal tears. Episiotomy angles that are too narrow and close to the midline increase the risk of obstetric anal sphincter injuries. In order to determine the optimal angle of the episiotomy, we assessed the changes in the angles of episiotomy lines marked during the first stage of labor and measured at the time of crowning of the head.