Twin pregnancies are associated with greater perinatal risks than singleton pregnancies, and due in part to caution over these risks, rates of elective cesarean births for twins have increased worldwide in recent years. Some observational data have suggested that vaginal delivery may increase adverse outcomes compared to elective cesarean, but there has been no strong evidence to recommend a policy of planned cesarean delivery in pregnancies without specific indications. A recent large randomized trial compared the delivery strategies of planned vaginal delivery and planned cesarean section in 2,804 twin pregnancies in which the first twin was presenting cephalically.
Women with twin pregnancy (gestational age 32 weeks to 38 weeks and 6 days) were randomized to planned vaginal delivery (with cesarean section only if indicated) vs. planned cesarean section. Inclusion criteria included first twin in cephalic presentation and expected birth weight of both twins 1,500-4,000 g (3.3-8.8 lbs) confirmed by ultrasound < 7 days before randomization. In cases of non-cephalic presentation of the second twin in the planned vaginal delivery group, the delivery method was at the discretion of the obstetrician, and could include total breach extraction, external cephalic version with cephalic vaginal delivery, or cesarean section. Exclusion criteria included monoamniotic twins, fetal reduction at ≥ 13 weeks gestational age, and contraindication to labor or vaginal delivery. Mothers and neonates were followed to 28 days after delivery. The primary outcome was a composite of fetal or neonatal death and serious neonatal morbidity.
Cesarean deliveries were performed in 90.7% of the planned cesarean group. In the planned vaginal delivery group, 39% had cesarean delivery for both twins and 4.2% had cesarean for the second twin only. The rates of the composite primary outcome were 1.9% with planned vaginal delivery vs. 2.2% with planned cesarean (not significant). Fetal or neonatal death occurred in 0.6% with planned vaginal delivery and 0.9% with cesarean, and serious neonatal morbidity occurred in 1.3% of each group. There were no significant differences in rates of maternal death or serious morbidity between groups. This trial suggests one way in which the current high rates of cesarean section may safely be reduced.
For more information, see the Multiple gestation topic in DynaMed.