Objective: The purpose of this study was to determine whether the maximum dose of oxytocin impacts the risk of uterine rupture in women who attempt vaginal birth after cesarean delivery (VBAC).
Study design: We conducted a retrospective, multicenter cohort study of women with a history of cesarean delivery. We compared uterine rupture rates between VBAC candidates that did and did not receive oxytocin, analyzing the association between maximum dose of oxytocin and uterine rupture. Bivariate and multivariate analyses were performed.
Results: Of the 13,523 patients who elected a VBAC trial, 128 women experienced a uterine rupture; 80 of these ruptures were in women who received oxytocin (62.5%). There was evidence of "dose response" for maximum oxytocin amount and uterine rupture, with a uterine rupture rate of 2.07% (adjusted odds ratio, 2.98; 95% CI 1.51-5.90) at the highest dosages.
Conclusion: In VBAC attempts, a dose-response relationship of maximum oxytocin and uterine rupture exists. These results provide evidence for vigilance when higher doses of oxytocin are given to patients who attempt VBAC.