Objective To evaluate the maternal and neonatal morbidity of operative vaginal delivery in relation to the use of episiotomy.
Design Prospective cohort study.
Setting Two urban maternity units in Scotland and England.
Population All nonrandomised nulliparous women delivered by forceps or vacuum during the recruitment period of a clinical trial evaluating the use of episiotomy at operative vaginal delivery.
Methods Use of episiotomy was compared to no episiotomy for all operative vaginal deliveries with sub-group analyses for forceps or vacuum deliveries.
Main outcome measures The primary outcome was anal sphincter tearing (third or fourth degree). Secondary outcomes included postpartum haemorrhage, neonatal trauma and pelvic floor symptoms up until 10 days postpartum.
Results A total of 1360 women were included in the study, of whom 294 (21.6%) did not receive an episiotomy. Vacuum delivery was associated with less use of episiotomy than forceps (56.1 versus 89.4%, OR 0.15, 95% CI 0.11–0.20). Anal sphincter tear rates were not statistically different with use of episiotomy compared with no episiotomy (9.9 versus 7.1%, adjusted OR 1.11, 95% CI 0.66–1.87). Episiotomy use was associated with higher rates of postpartum haemorrhage (28.5 versus 18.4%, adjusted OR 1.72, 95% CI 1.21–2.45), need for moderate or strong analgesia (90.5 versus 67.6%, adjusted OR 3.70, 95% CI 2.60–5.27), perineal infection (5.1 versus 1.4%, adjusted OR 4.04, 95% CI 1.44–11.37) and neonatal trauma (38.1 versus 22.0%, adjusted OR 1.65, 95% CI 1.20–2.27). Use of episiotomy did not reduce the risk of shoulder dystocia (3.5 versus 1.7%, adjusted OR 1.42, 95% CI 0.53–3.85).
Conclusions The use of episiotomy did not reduce or greatly increase anal sphincter tears and was associated with greater maternal and neonatal morbidity. This may reflect the complexity of deliveries. The role of episiotomy at operative vaginal delivery should be evaluated in a randomised controlled trial.