Objective: To determine whether early initiation of neuraxial analgesia (anesthetic[s] placed around the nerves of the central nervous system) compared with systemic opioid analgesia, followed later in labor by epidural analgesia, increases the rate of cesarean delivery in nulliparas undergoing induction of labor.
Methods: Nulliparas undergoing induction of labor who requested analgesia when cervical dilation was less than 4 cm participated in the study. Patients were randomized to neuraxial (early) or systemic opioid (late) analgesia at the first analgesia request. Patient-controlled epidural analgesia was initiated in the early group at the second analgesia request and in the late group at cervical dilation of 4 cm or greater or at the third analgesia request. The primary outcome was the rate of cesarean delivery.
Results: The rate of cesarean delivery was not different between groups (neuraxial [early] 32.7% compared with systemic [late] 31.5%, 95% confidence interval of the difference -3% to 6%, P=.65). A sample size of 30,500 would be required to detect a difference at the observed rate. There were no differences in the mode of vaginal delivery or Apgar scores. Pain scores were significantly lower (median 1 compared with 5 on a 0-10 scale, P<.001) and labor duration shorter (median 528 minutes compared with 569 minutes, P=.047) in the early group. The incidence of reassuring fetal heart rate tracings after analgesia was not different between groups.
Conclusion: Early-labor neuraxial analgesia does not increase the cesarean delivery rate compared with late epidural analgesia in nulliparas undergoing induction of labor.