The impact on labor of delaying epidural analgesia in nulliparous patients: a randomized trial

OBJECTIVE: To evaluate the effect on labor of delaying epidural analgesia until cervical dilation is ≥5 cm in actively managed nulliparous patients at term. STUDY DESIGN: Nulliparous women (n=103) at ≥36 weeks' gestation in spontaneous labor and undergoing active management of labor were recruited at the time of diagnosis of labor for this randomized trial. Upon request for analgesia, enrolled patients were assigned to either epidural placement at the time of patient request (group 1) or delay until ≥5 cm cervical dilation (group 2). Group 1 patients received either narcotic or epidural analgesia at their request independent of cervical dilation. Group 2 patients received narcotic analgesia until a cervical dilation of ≥5 cm was readied. Patients indicated their pain scores on a visual analog scale at 60-minnte intervals during the first stage of labor. The power to detect a difference between the two groups in proportion of patients receiving oxytocin augmentation and for all labor intervals evaluated was >0.8. RESULTS: Cervical dilation at diagnosis of labor and at request for analgesia were similar for the two groups, but the groups differed in dilation at epidural placement (3.9±1.2 cm vs. 5.1±1.1 cm, p<.001). The two groups did not differ in the length of the first or second stage of labor, rate of cervical dilation from the time of randomization to complete dilation, proportion of patients augmented, the maximum rate of oxytocin infusion, or the rate of instrumental delivery. There was also no difference in the incidence of OP or OT presentations at the time of delivery. The pain scores for group I were significantly lower at 60 and 120 minutes after randomization compared to group 2. For patients assigned to group 1 (n=55), the overall CS rate was 5.5% compared to 12.5% for group 2 (n=48, p=.18). CS rates for dystocia were 5.5% for group 1 and 6.3% for group 2. CONCLUSION: Among nulliparous patients who are actively managed, the policy of delaying epidural analgesia until ≥5 cm cervical dilation did not result in a shortening of the first or second stage of labor, faster rates of cervical dilation, decreased oxytocin use, or a decrease in malposition, instrumental delivery, or CS for dystocia.