A prospective study of two dosing regimens of oxytocin for the induction of labor in patients with unfavorable cervices

Abstract

The ideal regimen for induction of labor with oxytocin with respect to the magnitude and frequency of dosage changes has not been defined. In spite of few data regarding labor induction with an unfavorable cervix, the initial dose recommended by the American College of Obstetricians and Gynecologists is lower than that of other commonly used protocols. Eighty patients with unfavorable cervices and unruptured membranes, without evidence of labor, were randomized to one of two protocols and met criteria for data analysis. Patients in both protocols were given an initial dose of oxytocin of 2 mU/min. Patients in protocol A (n = 32) then received incremental increases of oxytocin of 1 mU/min at 30-minute intervals, while those in protocol B (n = 48) received incremental increases of 2 mU/min at 15-minute intervals. Induction failures were higher among patients on protocol A (31% vs 8%, p less than 0.05). Patients on protocol B had shorter times to delivery (mean = 10 hours 57 minutes vs 8 hours 3 minutes; p less than 0.05). The number of operative deliveries were similar regardless of protocol. There were no significant differences (p = NS) among groups and protocols in maternal and fetal complications, cesarean section rate, and uterine hyperstimulation. In this population a more aggressive protocol may lead to fewer induction failures and shorter induction-to-delivery intervals.