The trial was a massive logistic effort conducted at 106 centers in 25 countries; it took 7.5 years to recruit the requisite number of participants. As would be expected in a large number of twins, approximately 47% of all the births occurred before 37 weeks of gestation. More than 96% of all the first twins were in the cephalic presentation. The second twins were in a noncephalic presentation in approximately 39% of the women in the planned-cesarean-delivery group and in 36.4% of those in the planned-vaginal-delivery group. In the planned-cesarean-delivery group, 89.9% of the women underwent cesarean section for the delivery of both twins. In the planned-vaginal-delivery group, 56.2% of the women delivered both babies vaginally, whereas 39.6% underwent cesarean section for both babies (29.6% during labor and 14.1% before the onset of labor).