Cohort Study of Maternal and Neonatal Morbidity in Relation to Use of Episiotomy at Instrumental Vaginal Delivery

Abstract

The question of how best to manage instrumental deliveries-in particular, the role of episiotomy-has not been definitively answered. Randomized studies have suggested that significant benefits accrue when following a restrictive policy of episiotomy compared with its routine use during spontaneous vaginal birth. In this retrospective, population-based, cohort study, the investigators compared maternal and neonatal morbidity as related to the use of episiotomy in 2153 women having forceps or vacuum deliveries in the years 1998 to 2002. Participants all delivered a live singleton infant in cephalic vertex presentation at 37 weeks gestation or later. Consultants, middle-grade trainees, and senior house officers all took part in the study. Vacuum delivery was carried out in 29% of cases and forceps delivery in 71%. No episiotomy was performed in 241 women, 11% of the total. Episiotomy was done more often in nulliparous women, those given spinal anesthesia, when the second stage of labor was prolonged, and when the fetus was malpositioned. More women having forceps deliveries underwent episiotomy compared with those having vacuum delivery. Both the least and the most experienced obstetricians used episiotomy less often than did obstetricians with average experience. All 32 women in whom more than one instrument was used did have episiotomy; they were excluded from morbidity estimates. The perineum remained intact in 18% of cases without episiotomy. Third- and fourth-degree perineal tears were likelier when episiotomy was done, even after adjusting for possibly confounding antenatal and intrapartum factors. Infants were injured more often when episiotomy was done (adjusted odds ratio, 2.62), but serious neonatal trauma was infrequent and no infants died. Shoulder dystocia was not less frequent when episiotomy was done routinely. Morbidity related to the use of episiotomy was similar for vacuum and forceps deliveries. In this study, the risk of severe perineal tears was higher when episiotomy was performed as part of an instrumental delivery. At the same time, the risk of shoulder dystocia was not lessened. It is possible that routine episiotomy in the setting of instrumental delivery does more harm than good.