Perinatal outcome after planned vaginal delivery in monochorionic compared with dichorionic twin pregnancy

OBJECTIVE To assess, according to chorionicity, the perinatal outcome of twin pregnancy in which vaginal delivery is planned. METHODS JUMODA (JUmeaux MODe d'Accouchement) was a national prospective population-based cohort study of twin pregnancies, delivered in 176 maternity units in France, from February 2014 to March 2015. In this planned secondary analysis, we assessed, according to chorionicity, the perinatal outcome of twin pregnancies, in which vaginal delivery was planned, that delivered at or after 32 weeks of gestation with the first twin in cephalic presentation. In order to select a population with well-recognized indications for planned vaginal delivery, we applied the same exclusion criteria as those in the Twin Birth Study, an international randomized trial. Monochorionic twin pregnancies with twin-to-twin transfusion syndrome or twin anemia-polycythemia sequence were defined as complicated and were excluded. The primary outcome was a composite of intrapartum mortality and neonatal morbidity and mortality. Multivariable logistic regression models were used to control for potential confounders. Subgroup analyses were conducted according to birth order (first or second twin) and gestational age at delivery (