Objective: To evaluate which intrapartum factors influence the method of delivery in a group of twin pregnancies eligible for vaginal delivery.
Study design: Over a 10-year period, 967 consecutive twin pregnancies at gestational age >/=32 weeks with twin A presenting as a vertex and eligible for vaginal delivery were reviewed. Excluded were 40 (4.1%) patients who underwent a repeat and elective cesarean section. All patients who underwent a cesarean section were placed into one of two groups according to the method of delivery of both twins: group 1, cesarean section/cesarean section delivery; and group 2, vaginal/cesarean section delivery. The impact of the following intrapartum factors on the type of delivery were assessed: (1) presentation of the 2nd twin: vertex vs. breech vs. other; (2) experience of the obstetrician: </=euro 10 years vs. > 10 years in practice; (3) multiparity: nulliparous vs. multiparous; (4) incidence of epidural usage; (5) induction vs. spontaneous labor; and (6) difference in fetal weight between twin B and twin A: <euro 25% difference vs. >/= 25% difference. The chi-square statistic was used to compare differences in the incidence of cesarean section between the groups.
Results: Total incidence of cesarean section was 266/927 (28.7%). Risk of delivering by a combined vaginal delivery and cesarean section was reduced if the presentation of twin B was vertex or breech (RR: 0.114; 95% confidence interval: 0.049-0.266) or if an epidural was used (RR: 0.380; 95% confidence interval: 0.163-0.883). In twin gestations eligible for vaginal delivery the risk of requiring delivery by cesarean section for both twins is reduced if the presentation of twin B was vertex (RR: 0.782; 95% confidence interval; 0.631-0.968), if an epidural was used (RR: 0.461; 95% confidence interval: 0.375-0.566), or if the birthweight discrepancy was <euro25% (RR: 0.695; 95% confidence interval: 0.524-0.922).
Conclusion: Twin gestations with twin B presenting as vertex or breech or with an epidural were less likely to undergo combined vaginal delivery and cesarean section. The liberal use of epidural anesthesia may reduce the need for cesarean section in patients with twin gestations considered good candidates for vaginal delivery.