Does the morbidity of twin gestations after 36 weeks increase with advancing gestational age?

Objective: Given that fetal growth rates peak 4 weeks earlier in twin compared with singleton gestations and that the mean gestational age at delivery of twin gestations is reported to be 35-36 weeks, we postulated that postdates morbidity might also occur 4 weeks earlier in twin gestations. This study examined whether twins delivered ≥ 38 weeks had a higher perinatal morbidity than twins delivered between 36 and 37.9 weeks. Methods: Two hundred and ten sets of twins (control group) delivered between 36 and 37.9 weeks were compared to 147 sets of twins (study group) delivered at ≥ 38 weeks gestational age. The two groups were analyzed for differences in maternal demographic characteristics, intrapartum factors and neonatal outcome. Results: No significant differences were detected in neonatal outcome except for an increase in the proportion of control group patients with hyperbilirubinemia and hypoglycemia. Conclusions: Twins delivered at ≥ 38 weeks have decreased perinatal morbidity compared to twins delivered at 36-37.9 weeks.