Please exit safely: maternal and twin pair neonatal outcomes according to delivery mode when twin A is vertex.

Objective: To investigate maternal and infant outcomes associated with delivery mode for twins with a cephalic presenting twin.

Methods: Linked birth certificate and ICD hospital discharge data were analyzed retrospectively for 5573 mothers and their respective twin pairs born live at 34-42 weeks' gestation, with twin A vertex, in Washington State from 1997-2007. Relative risks (RR) and 95% confidence intervals of adverse maternal and twin pair outcomes were calculated for vaginal delivery or cesarean during labor in comparison to cesarean without labor.

Results: Vaginal delivery or cesarean during labor was associated with significantly elevated rates of maternal hemorrhage (RR = 2.8 [2.2,3.7]), infection (RR = 2.2 [1.5,3.3]), twin pair birth injury (RR = 2.6 [1.2,5.4]) and low 5-min Apgar scores (RR = 1.4 [1.1,1.8]) and with significantly lower rates of ventilation among preterm twin pairs only (RR = 0.8 [0.7,0.9]). The lowest rate of combined poor short-term outcomes occurred in mothers and twin pairs delivered by cesarean without labor (23%) and the highest rates occurred in those with operative vaginal or cesarean during labor (39% and 34%, respectively). Among women in labor, 35% of nulliparas achieved spontaneous vaginal delivery of both twins compared to 63% of non-nulliparas.

Conclusion: For nulliparous women who carry twins to term, planned cesarean may improve outcomes.