The Risk of Cesarean Delivery With Neuraxial Analgesia Given Early versus Late in Labor

The recommendation that epidural anesthesia be delayed in nulliparous women until there is 4–5 cm of cervical dilatation rests on an increased risk of cesarean delivery at less than 4.0 cm. It is not clear whether this is a result of the analgesia or other factors. The authors postulated that neuraxial analgesia administered early in labor using intrathecal opioid, as part of a low-dose local anesthetic technique, would not increase the risk of operative delivery. A randomized trial enrolled 728 nulliparous women at term who either were in spontaneous labor or had spontaneous rupture of membranes and whose cervical dilatation was less than 4.0 cm. The participants received either intrathecal fentanyl, with bupivacaine added as needed, or systemic (intravenous and intramuscular) hydromorphone when they first asked for analgesia. Epidural analgesia was started at the second request for analgesia in the intrathecal group, and at cervical dilatation of 4.0 or more, or at the third request for pain relief in the systemic group. Rates of cesarean delivery did not differ significantly between the 2 groups, and there also were no significant differences in the rate of instrumental vaginal delivery or indications for operative delivery. The maximum rate of oxytocin infusion was, however, higher in women given systemic analgesia. Neither type of insurance (private or public) nor different obstetric providers made a difference. Times from initial analgesia to complete dilatation and vaginal delivery were significantly shorter when intrathecal analgesia was used. The intrathecal group had less nausea and vomiting, and neuraxial analgesia lasted longer in this group than in women given systemic analgesia. There was no significant group difference in worrisome fetal heart rate tracings. The findings in this randomized trial indicate that nulliparous women in spontaneous labor, or having spontaneous membrane rupture, may receive neuraxial analgesia early in the course of labor without adverse effects. Early neuraxial analgesia does not appear to increase the number of cesarean deliveries compared with systemic opioid analgesia, and it may shorten labor.