Maternal and system characteristics, oxytocin administration practices, and cesarean birth rate

The cesarean birth rate in the United States is 32%, and there is discussion about the cause of high surgical birth rates. Our purpose was to determine whether mode of birth is influenced by maternal, nurse, and system factors.

Secondary analysis of a data set of 163 women having postdates labor induction with oxytocin. Kaplan-Meier survival curves were calculated to compare the time for patients to reach an infusion rate of 6 mU/min, consistent with endogenous oxytocin levels in active labor. We used the log-rank test to evaluate survival curve differences. Multiple logistic regression and Cox proportional hazards models were conducted and included covariates that had statistically significant bivariate relationships with the time variable, or were clinically meaningful.

The mean time to reach 6 mU/min was longer for women who birthed by cesarean (172.5 minutes) than for women who had vaginal birth (125.0 minutes, P = .024). The mean time to reach 6 mU/min was also longer for women admitted on night shift (147.0 minutes) than day shift (110.2 minutes, P = .018). No maternal characteristics were significantly related to the time to reach a rate of 6 mU/min.

Even during the initial hours of labor induction, it is important that the oxytocin infusion is titrated appropriately to aid women in achieving timely vaginal birth. Intrapartum nurses should receive education about the pharmacokinetics of intravenous oxytocin to understand proper administration of this high-alert medication.