Comparative effectiveness of intravenous remifentanil, epidural anesthesia, and a 2-step analgesic approach for...

Among the analgesic strategies used during external cephalic version, neuraxial anesthesia is the only approach that has consistently demonstrated higher vaginal delivery rates. However, neuraxial analgesia encompasses a heterogeneous range of techniques, and higher complication rates have been reported compared with other approaches.

This study aimed to compare the success of external cephalic version, modes of delivery, maternal pain, and complications using 3 strategies: intravenous analgesia with remifentanil, epidural anesthesia, and a stepwise approach in which epidural anesthesia was administered only if intravenous analgesia was unsuccessful.

We conducted a single-center, consecutive 3-phase cohort study including 1963 singleton pregnancies undergoing an external cephalic version: 558 with intravenous remifentanil (Group 1, 2012-2015), 665 with intravenous remifentanil followed by epidural anesthesia 2 to 3 days later if unsuccessful (Group 2, 2016-2019), and 730 under epidural anesthesia (Group 3, 2020-2024), yielding 2218 procedures, 1233 with intravenous remifentanil and 985 with epidural anesthesia. All procedures followed a standardized protocol, performed or supervised by experienced obstetricians, with continuous presence of anesthesiologists. Ritodrine was administered for tocolysis, or atosiban when contraindicated. Outcomes included success of the external cephalic version, mode of delivery, maternal pain (0-10 numerical scale), any analgesia-related complications, and procedural-related obstetric complications including vaginal bleeding, abnormal fetal heart rate patterns, hospital admission, or any event that led to a delivery. Chi-square test was used for comparison, with significance at P<.05.

Success rates were highest with epidural anesthesia (70.0%, 511/730), compared with intravenous remifentanil (52.2%, 291/558) and the stepwise approach (65.2%, 440/675; P<.001). This was reflected in vaginal delivery rates of 72.2% (526/730), 64.0% (342/534), and 66.1% (444/672), respectively (P=.005). Maternal pain was substantially lower under epidural, with 78.3% of women reporting no or minimal pain, whereas this proportion fell to 49.2% in the remifentanil group and to 36.2% in the 2-step approach (P<.001). Adverse effects of anesthesia were generally uncommon and clinically mild, but higher with epidural anesthesia (P<.001). Maternal hypotension was the main complication under epidural anesthesia (16.1%, 159/985), followed by dizziness (3.7%, 36/985), neither associated with significant obstetric clinical consequences. Procedural complications were rare, but more common with epidural anesthesia, and overall, highest among patients undergoing the 2-step approach (P=.264). Vaginal bleeding occurred in 3.6% (35/985) of epidural cases and 4.3% (53/1233) with remifentanil (P=.052). Abnormal fetal heart rate patterns were more frequent with epidural (3.6%, 35/985) than with remifentanil (1%, 12/1233) (P<.001). Procedure-related hospital admissions were uncommon and similar (3.6%, 35/985 vs 3.6%, 45/1233). Procedure-related deliveries and urgent cesareans were rare, but higher with epidural (1.4%, 15/985) than with remifentanil (0.5%, 6/1233) (P=.021).

In this study, a single attempt with epidural anesthesia was the most effective strategy for external cephalic version, achieving the highest success and vaginal delivery rates while providing superior maternal pain control, but with higher complications. These findings may help support more informed counseling and shared decision-making when discussing analgesic options for external cephalic version.