A Multicenter, Randomized, Controlled Trial Comparing Bupivacaine with Ropivacaine for Labor Analgesia

Abstract

Background A meta-analysis of studies comparing high doses of bupivacaine with ropivacaine for labor pain found a higher incidence of forceps deliveries, motor block, and poorer neonatal outcome with bupivacaine. The purpose of this study was to determine if there is a difference in these outcomes when a low concentration of patient-controlled epidural bupivacaine combined with fentanyl is compared with ropivacaine combined with fentanyl. Methods This was a multicenter, randomized, controlled trial, including term, nulliparous women undergoing induction of labor. For the initiation of analgesia, patients were randomized to receive either 15 ml bupivacaine, 0.1%, or 15 ml ropivacaine, 0.1%, each with 5 microg/ml fentanyl. Analgesia was maintained with patient-controlled analgesia with either local anesthetic, 0.08%, with 2 microg/ml fentanyl. The primary outcome was the incidence of operative delivery. We also examined other obstetric, neonatal, and analgesic outcomes. Results There was no difference in the incidence of operative delivery between the two groups (148 of 276 bupivacaine recipients vs. 135 of 279 ropivacaine recipients; P = 0.25) or any obstetric or neonatal outcome. The incidence of motor block was significantly increased in the bupivacaine group compared with the ropivacaine group at 6 h (47 of 93 vs. 29 of 93, respectively; P = 0.006) and 10 h (29 of 47 vs. 16 of 41, respectively; P = 0.03) after injection. Satisfaction with mobility was higher with ropivacaine than with bupivacaine (mean +/- SD: 76 +/- 23 vs. 72 +/- 23, respectively; P = 0.013). Satisfaction for analgesia at delivery was higher for bupivacaine than for ropivacaine (mean +/- SD: 71 +/- 25 vs. 66 +/- 26, respectively; P = 0.037). Conclusions There was no difference in the incidence of operative delivery or neonatal outcome among nulliparous patients who received low concentrations of bupivacaine or ropivacaine for labor analgesia.