Labor Analgesia and Cesarean Delivery: An Individual Patient Meta-analysis of Nulliparous Women

Background: The authors performed an individual patient meta-analysis of 2,703 nulliparous women who were randomized to either epidural analgesia or intravenous opioids for pain relief during labor from five trials conducted at their hospital. The primary purpose in this meta-analysis was to evaluate the effects of epidural analgesia during labor on the rate of cesarean delivery. Methods: Between November 1, 1993, and November 3, 2000, 2,703 nulliparous women (2,188 healthy parturients and 515 women with pregnancy-induced hypertension) in spontaneous labor at term were randomized to receive either epidural analgesia or intravenous opioid analgesia in the five studies. Epidural analgesia was initiated with either epidural bupivacaine or intrathecal sufentanil and was maintained with a low-dose (0.0625% or 0.125%) mixture of bupivacaine with fentanyl. Intravenous opioid analgesia was initiated with 50 mg meperidine and 25 mg promethazine hydrochloride and was maintained with intravenous boluses of meperidine as needed. Results: A total of 1,339 nulliparous women were randomized to receive epidural analgesia, and 1,364 women were randomized to receive intravenous meperidine analgesia. There was no difference in the rate of cesarean deliveries between the two analgesia groups (epidural analgesia, 10.5% [140 of 1,339] vs. intravenous meperidine analgesia, 10.3% [141 of 1,364]; adjusted odds ratio, 1.04; 95% confidence interval, 0.81-1.34; P = 0.920). Significantly more women randomized to epidural analgesia had forceps deliveries compared to meperidine analgesia (13% [172 of 1,339] vs. 7% [101 of 1,364]; adjusted odds ratio, 1.86; 95% confidence interval, 1.43-2.40; P < 0.001). Epidural women had longer first and second stages of labor. Women who received epidural analgesia reported lower pain scores during labor and delivery compared to women who received intravenous meperidine analgesia. Conclusion: Epidural analgesia compared to intravenous meperidine analgesia during labor does not increase the number of cesarean deliveries.