Vaginal birth after cesarean (VBAC) in twin pregnancies: Is it safe?


      To compare the rate of VBAC attempt, VBAC failure, and major adverse outcomes in women with twin and singleton pregnancies.

      Study design

      We performed a multicenter retrospective cohort study between the years 1996 and 2000. Subjects were identified by ICD-9 code (“previous cesarean section”). Trained research nurses collected data on success and failure of VBAC attempts, and major clinical outcomes including uterine rupture, major operative injuries, hemorrhage, and composite adverse outcome (uterine rupture, bladder injury, and uterine artery laceration). We used logistic regression to assess the association between twins and the outcomes, adjusting for confounding.


      Of 24,842 patients, there were 535 twin pregnancies and 24,307 singleton pregnancies. Outcomes are displayed below.
      Tabled 1
      OutcomesTwin (n=535)Singleton (n=24307)Unadjusted RR (95%CI)Adjusted OR (95%CI)
      VBAC attempt177 (33.1%)13427 (55.2%)0.6 (0.5-0.7)0.3 (0.2-0.4)
      Failed VBAC43 (24.3%)3306 (24.6%)1.0 (0.8-1.3)1.1 (0.8-1.6)
      Uterine rupture2 (1.1%)125 (0.9%)1.2 (0.3-4.9)-
      Composite6 (3.4%)292 (2.2%)1.6 (0.7-3.5)1.6 (0.7-3.7)


      In the largest reported series of women with twin pregnancies who attempted VBAC, we found that women with twin gestations were much less likely to undergo a VBAC trial, but were no more likely to fail a VBAC trial compared to women with singleton gestations. There is no difference in adverse maternal outcomes in women who VBAC with twins compared to singletons. Based on this data, women carrying twins should not be discouraged from undergoing a VBAC trial.