Influence of chorionicity in intra-partum management of twin deliveries.

Objective: To analyze morbidity and mortality in twin pregnancies as a function of the type of delivery and chorionicity. Design: Retrospective cohort study. Methods: Analysis of the type of delivery, intertwin time interval, and perinatal variables of >1000 twin deliveries during a 10-year period. Main outcome measure: Influence of delivery type and chorionicity on perinatal outcome. Results: The rate of cesarean sections was 42.4%. No differences were found as a function of chorionicity or as a function of presentation of the second twin. Cesarean sections were performed after vaginal delivery of the first twin in 1.8% of cases, being more common if the second baby was in a noncephalic presentation (6.9% vs. 0.4%, p < 0.05). The average twin-to-twin delivery time interval was longer in the cases where the second had a cephalic presentation (8.26 ± 7.75 min vs. 6.81 ± 5.97 min, p < 0.05). The umbilical artery pH was lower the longer the interval between the birth of the twins, both in monochorionic and dichorionic. Conclusions: According to the results, vaginal delivery is as safe as elective caesarean section in twin pregnancies where the first twin is in cephalic presentation and the intrapartum management should not vary due to chorionicity.