Background: Over the past two decades, the rate of cesarean section in the United States has risen from 5 percent to 25 percent of deliveries, primarily because of the increased frequency of dystocia (arrest of labor). One strategy that has been proposed for increasing the rate of vaginal delivery is a program of active management of labor that encourages early amniotomy, early diagnosis of slow progress in labor, and the use of higher than usual doses of oxytocin; the efficacy and safety of this approach are uncertain, however.
Methods: We conducted a randomized trial in which nulliparous women in spontaneous labor at term were randomly assigned to either active management of labor or traditional management. With active management, amniotomy was performed within one hour of the diagnosis of labor, and when the rate of cervical dilation was less than 1 cm per hour, oxytocin was infused at an initial rate of 6 mU per minute. The dose was increased by 6 mU per minute every 15 minutes (to a maximum of 36 mU per minute) until there were seven contractions every 15 minutes.
Results: For the women assigned to active management (n = 351), the cesarean-section rate was 10.5 percent, as compared with 14.1 percent for those assigned to traditional management (n = 354, P = 0.18). The 26 percent reduction in the cesarean-section rate was due primarily to a decrease in dystocia. After we controlled for potential confounding variables, the reduction in the rate of delivery by cesarean section was statistically significant (odds ratio for women given active as compared with traditional management, 0.57; 95 percent confidence interval, 0.36 to 0.95). With active management, the average length of labor was shortened by 1.66 hours, principally because of earlier amniotomy and earlier use of oxytocin. There was no increase in maternal or neonatal morbidity, and there were significantly fewer infectious complications in the mothers.
Conclusions: The program we studied for the active management of labor reduces the incidence of dystocia and increases the rate of vaginal delivery without increasing maternal or neonatal morbidity.