Highlights
- Epidural anesthesia achieved the highest success rate for external cephalic version (ECV) at 70.0%, compared to 52.2% for intravenous remifentanil.
- Vaginal delivery rates were significantly higher in the epidural group (72.2%) than in the remifentanil group (64.0%).
- Maternal pain control was superior with epidural anesthesia, with 78.3% of patients reporting minimal to no pain.
- While more effective, epidural anesthesia was associated with higher rates of maternal hypotension (16.1%) and transient fetal heart rate abnormalities (3.6%).
Introduction: The Challenge of the Breech Presentation
Breech presentation occurs in approximately 3% to 4% of term pregnancies and is a primary indication for planned cesarean delivery. External cephalic version (ECV)—the manual manipulation of the fetus into a cephalic presentation—remains the gold-standard intervention to reduce cesarean rates associated with malpresentation. However, the success of ECV is influenced by multiple factors, including parity, placental location, amniotic fluid volume, and, crucially, maternal relaxation and analgesia.
While various analgesic strategies have been employed to facilitate ECV, the literature has historically been divided on the optimal approach. Neuraxial techniques, such as epidural anesthesia, are thought to improve success by providing superior abdominal muscle relaxation and pain relief. Conversely, systemic opioids like remifentanil offer a less invasive alternative but may not provide the same degree of somatic blockade. This study, led by Aiartzaguena et al. (2026), provides a comprehensive comparison of these strategies in a large, single-center clinical setting.
Study Design and Methodology
This prospective, consecutive three-phase cohort study conducted at a single center evaluated 1,963 singleton pregnancies undergoing ECV. The study was structured into three distinct chronological groups to compare different analgesic protocols:
Experimental Groups
- Group 1 (2012–2015): Intravenous (IV) remifentanil administered to 558 patients.
- Group 2 (2016–2019): A stepwise approach involving 665 patients where IV remifentanil was the first-line treatment, followed by epidural anesthesia 2–3 days later if the initial attempt failed.
- Group 3 (2020–2024): Primary epidural anesthesia administered to 730 patients.
All procedures were performed or supervised by experienced obstetricians with continuous anesthesiology presence. Tocolysis was standardized using ritodrine (or atosiban if contraindicated). The primary endpoints included ECV success rates, mode of delivery, maternal pain scores (0–10 numerical scale), and both anesthesia-related and obstetric complications.
Results: Superior Efficacy of Epidural Anesthesia
The data demonstrated a clear hierarchical advantage for epidural anesthesia in terms of procedural success and subsequent delivery outcomes.
ECV Success and Vaginal Delivery Rates
The success rate for the ECV procedure was significantly higher in the epidural group (70.0%) compared to the remifentanil group (52.2%) and the stepwise approach (65.2%). This increased procedural success translated directly into improved birth outcomes. The vaginal delivery rate was 72.2% for women in the epidural group, compared to 64.0% in the remifentanil group and 66.1% in the two-step group (p = 0.005). These findings suggest that the choice of analgesia is not merely a matter of comfort but a critical determinant of the clinical pathway toward vaginal birth.
Maternal Pain Control
The subjective experience of the patients also varied significantly across the cohorts. Epidural anesthesia provided the most robust pain relief, with 78.3% of women reporting a pain score of 0 or 1. In contrast, only 49.2% of women in the remifentanil group and 36.2% in the stepwise group reported similar levels of comfort. The lower satisfaction in the stepwise group may be attributed to the cumulative stress of multiple procedures and the inherent discomfort of the initial failed remifentanil attempt.
Safety Profile and Procedural Complications
While epidural anesthesia showed superior efficacy, it was associated with a higher frequency of side effects and minor complications compared to systemic analgesia.
Anesthesia-Related Adverse Events
Maternal hypotension was the most frequent complication in the epidural group, occurring in 16.1% of cases. Dizziness was reported by 3.7% of these patients. However, these events were generally transient and did not lead to significant adverse clinical consequences for the mother or the neonate. In the remifentanil group, systemic side effects were less frequent but included typical opioid-related responses.
Obstetric and Fetal Outcomes
Fetal heart rate (FHR) abnormalities were more prevalent during procedures conducted under epidural anesthesia (3.6%) than those under remifentanil (1.0%; p < 0.001). Furthermore, the rate of urgent cesarean sections or procedure-related deliveries was higher in the epidural cohort (1.4%) compared to the remifentanil cohort (0.5%). Vaginal bleeding occurred at similar rates across both primary groups (3.6% for epidural vs. 4.3% for remifentanil). Importantly, the overall rate of procedure-related hospital admissions remained identical at 3.6% for both groups.
Expert Commentary: Balancing Efficacy and Risk
The findings by Aiartzaguena et al. underscore a classic clinical trade-off in obstetrics: the balance between maximizing the success of a beneficial intervention and minimizing procedural risk. The 17.8% absolute increase in ECV success with epidural anesthesia over remifentanil is clinically profound. For every six to seven epidurals performed instead of remifentanil, one additional successful version is achieved, potentially sparing a patient from a primary cesarean section.
However, the increased rate of FHR abnormalities and urgent deliveries in the epidural group cannot be ignored. The biological plausibility for these events may involve the sympathetic blockade associated with neuraxial anesthesia, leading to maternal hypotension and subsequent placental hypoperfusion. This necessitates a high degree of vigilance, including continuous fetal monitoring and the immediate availability of surgical facilities when using epidural anesthesia for ECV. The “two-step” approach, while theoretically appealing to minimize initial invasiveness, appears to be less efficient than a primary epidural strategy and results in the lowest patient satisfaction regarding pain management.
Conclusion
This large-scale cohort study provides strong evidence that a single attempt at external cephalic version under epidural anesthesia is the most effective strategy for achieving both procedural success and vaginal delivery. While it carries a slightly higher risk of manageable complications, the superior pain control and higher success rates make it a compelling option for many patients. These results should be integrated into shared decision-making processes, allowing expectant mothers to weigh the higher success and comfort of an epidural against the lower but present risks of maternal hypotension and fetal heart rate changes.
References
- Aiartzaguena A, Rodríguez L, Quintana E, et al. Comparative effectiveness of intravenous remifentanil, epidural anesthesia and a two-step analgesic approach for external cephalic version: a large prospective single-center cohort study. American Journal of Obstetrics and Gynecology. 2026.
- American College of Obstetricians and Gynecologists (ACOG). Practice Bulletin No. 161: External Cephalic Version. Obstetrics & Gynecology. 2016 (Reaffirmed 2023).
- Goetzler A, et al. Neuraxial Anesthesia for External Cephalic Version: A Meta-analysis. Anesthesia & Analgesia. 2021.