Module 10 ACOG Practice Bulletin: External Cephalic Version

Interim Update: ACOG Practice Bulletin Number 221

This practice bulletin offers comprehensive clinical management guidelines for obstetrician-gynecologists, emphasizing external cephalic version (ECV). This update highlights key changes regarding ECV in women with a history of cesarean birth and underscores the inverse relationship observed between a hospital's cesarean birth rate and the success rate of ECV procedures. The update also introduces a new Level B recommendation, advocating the use of neuraxial analgesia combined with tocolytic therapy to improve ECV outcomes significantly.

Background on External Cephalic Version (ECV)

The elevated cesarean birth rate in the United States is a significant concern within the healthcare community. Current efforts are focused on reducing these rates through changes in management practices. Breech presentations are strongly associated with higher cesarean birth rates, which has renewed interest in both ECV and vaginal breech delivery as viable alternatives.

ECV is a procedure that involves applying manual pressure to the maternal abdomen to manipulate the fetus into a vertex (head-down) presentation, thereby increasing the likelihood of a vaginal delivery. When ECV is unsuccessful, the subsequent mode of delivery should be determined by the healthcare provider's expertise, with planned vaginal breech delivery considered under specific conditions, including thorough patient counseling and adherence to established protocols.

Clinical Considerations and Recommendations for ECV

Candidate Selection

To facilitate timely consideration of ECV, fetal presentation should be systematically assessed and documented starting at 36 weeks of gestation. Performing ECV at or beyond 37 weeks is generally preferred. By this stage, the likelihood of spontaneous version is reduced, and the risk of spontaneous reversion following a successful ECV is minimized. While earlier attempts at ECV may show high initial success rates, they are also associated with increased reversion rates.

A randomized controlled trial indicated a small but significant reduction in noncephalic presentation at birth with early ECV (performed between 34 0/7 and 35 6/7 weeks) compared to ECV performed at or after 37 weeks ($RR = 0.84$, 95% CI, 0.75–0.94, $P=0.002$). However, this reduction was noted without significant differences in either cesarean birth rates or preterm birth rates (10).

A pooled data review from three studies (totaling 1,906 participants) suggested that earlier ECV (between 34 and 35 weeks) could reduce the incidence of noncephalic presentation at birth ($RR = 0.81$, 95% CI, 0.74–0.90). Further analysis of 1,888 participants indicated a reduced rate of failure to achieve cephalic vaginal birth ($RR = 0.90$, 95% CI, 0.83–0.97), but also highlighted an increased risk of preterm labor ($RR = 1.51$, 95% CI, 1.03–2.21). Therefore, the potential risk of preterm birth must be carefully weighed against the anticipated benefits of ECV.

In the event of complications arising during the ECV procedure, the capability to perform an emergency cesarean delivery of a term infant is crucial.

ECV with Previous Uterine Scar

Data regarding ECV attempts in women with a prior uterine scar or during early labor are limited. Information on women with a prior cesarean delivery is primarily derived from retrospective case-control analyses. Seven studies compared women undergoing ECV with one prior cesarean (total n = 500) to multiparous women without a prior cesarean. An additional trial analyzed a U.S. administrative dataset from 2012 to 2014, which included 715 women undergoing ECV with one previous cesarean.

The reported success rates varied across these studies. One study found a significantly higher ECV success rate in women with a previous cesarean, while three studies reported a significantly lower rate, and four studies showed no significant difference. The overall successful ECV rate in women with a previous cesarean ranged from 50% to 84%. Importantly, no cases of uterine rupture during ECV were reported in these trials.

ECV During Early Labor

There are scattered reports documenting successful ECV performance during early labor. Data from the Nationwide Inpatient Sample (1998 to 2011), analyzing ECV attempts during delivery admission, indicated a 65% success rate. This success led to a significantly lower cesarean birth rate and a reduced likelihood of hospital stays longer than 7 days, compared to cases of persistent breech presentation.

Contraindications

ECV is contraindicated when vaginal delivery is deemed clinically inappropriate. Specific absolute or relative contraindications are not definitively established and should be determined on a case-by-case basis.

Benefits and Risks of ECV

The primary benefit of a successful ECV is the increased likelihood of achieving a vertex presentation at delivery, which aims to facilitate an uncomplicated vaginal delivery. Research indicates that women with successful ECV experience fewer cesarean births compared to those who do not undergo ECV attempts. Furthermore, successful ECV is associated with reduced hospital charges, shorter hospital stays, and decreased odds of endometritis and sepsis.

A comprehensive review evaluating the impact of ECV on breech presentation near term (involving 1,308 participants) demonstrated a significant reduction in noncephalic presentation at birth ($RR = 0.42$, 95% CI, 0.29–0.61), a reduced failure to achieve cephalic vaginal birth ($RR = 0.46$, 95% CI, 0.33–0.62), and fewer cesarean births ($RR = 0.57$, 95% CI, 0.40–0.82). No significant differences were observed in low Apgar scores, umbilical vein pH, or neonatal death rates.

Adverse events following ECV, such as abruptio placentae, umbilical cord prolapse, rupture of membranes, stillbirth, and fetomaternal hemorrhage, occur at rates of less than 1%. Fetal heart rate changes are commonly observed during ECV but typically stabilize once the procedure is halted.

A report from Copenhagen described two intrauterine deaths occurring 2 and 5 weeks after ECV among 316 women, as well as one instance of premature partial placental separation 2 days after a failed ECV. However, a direct causal link to ECV could not be established in these cases. A study involving pregnant women at 36 weeks or earlier reported two cases of abruptio placentae and one case of premature labor shortly after ECV, resulting in one neonatal and two fetal deaths. Subsequent changes in management practices and selection criteria led to a follow-up study that reported no fetal deaths directly attributable to ECV.

One study documented a case of abruptio placentae during an ECV attempt, which required an emergency cesarean delivery and was the only major complication attributed to ECV among 113 women. Given the low incidence of complications, ECV should be performed in settings equipped for prompt evaluation and cesarean delivery.

Success Rates and Predictive Factors

A meta-analysis assessing ECV-related risks reported success rates ranging from 16% to 100%, with a pooled success rate of 58% and a pooled complication rate of 6.1%. Parity is positively correlated with successful version, and transverse or oblique fetal presentations have higher immediate success rates. An inverse relationship exists between a hospital's cesarean birth rate and successful ECV outcomes.

Successful ECV was approximately one-third lower among women delivering at hospitals with cesarean birth rates exceeding 35%, compared to those with rates below 20%. Scoring systems designed to predict successful ECV are subject to debate, and the utility of factors such as amniotic fluid volume, placenta location, and maternal weight remains unclear. Some reports suggest that normal or increased amniotic fluid levels are associated with successful ECV, while others do not. Similarly, the correlation between placenta location and obesity with ECV success varies across different studies. Factors such as nulliparity, advanced cervical dilatation, fetal weight less than 2,500 grams, anterior placenta location, and low fetal station are associated with ECV failure.

Impact of Tocolysis

A randomized study involving terbutaline found that the ECV success rate nearly doubled with its use. Most studies either routinely or selectively employ a tocolytic agent. An extensive review of 28 studies (totaling 2,706 participants) concluded that parenteral ß-stimulant tocolysis is more effective in achieving cephalic presentation during labor ($RR = 1.68$, 95% CI, 1.14–2.48). Subsets of these studies also indicated a reduction in cesarean births ($RR = 0.77$, 95% CI, 0.67–0.88) and a decreased rate of failure to achieve cephalic vaginal delivery ($RR = 0.75$, 95% CI, 0.60–0.92). Current evidence supports the use of parenteral tocolysis to enhance ECV success. However, there is insufficient data to adequately assess the adverse effects of b-stimulant tocolysis, and the use of nitric oxide donors is discouraged.

Impact on Cesarean Birth Rates

The extent to which ECV reduces cesarean birth rates is contingent on various factors, most notably the success rate of the ECV procedure itself. Women who undergo successful ECV generally have lower cesarean birth rates. Randomized studies have demonstrated a significant decrease in cesarean birth rates among patients assigned to ECV. Retrospective studies comparing cesarean birth rates after successful ECV with rates observed in spontaneous cephalic presentations have yielded mixed results.

A meta-analysis reported increased odds of cesarean birth following successful ECV compared to cephalic presentation (11 studies, odds ratio 2.2, 95% CI 1.7–2.8). Nevertheless, more recent reviews suggest that ECV is associated with an overall reduction in cesarean births. Factors that may diminish the observed differences between ECV and non-ECV groups include spontaneous conversion of presentation and the willingness to perform vaginal breech deliveries. Additionally, the necessity for cesarean delivery due to other obstetrical indications can also lessen ECV's overall impact.

ECV is recognized as a valuable management technique that poses minimal risk to both the mother and fetus. Successful ECV provides an opportunity for vertex vaginal delivery. Given the low risk of adverse events and the significantly lower cesarean birth rate among women with successful ECV, all near-term women with breech presentations should be offered ECV, provided no contraindications are present.

Impact of Anesthesia

Individual studies have reported greater ECV success rates with the use of epidural anesthesia, although these findings may be subject to bias. Epidural anesthesia has also been suggested for women who have experienced previous failed ECV attempts. One randomized trial found no significant difference in ECV success with spinal anesthesia, whereas another observed a significant improvement with spinal analgesia plus tocolysis compared to tocolysis alone (87.1% versus 57.5%, $P=0.009$, 95% CI, 0.075–0.48).

A meta-analysis (9 studies, n = 934) indicated that neuraxial analgesia combined with tocolytics was associated with a higher incidence of successful ECV ($RR = 1.44$, 95% CI, 1.27–1.64), cephalic presentation during labor ($RR = 1.37$, 95% CI, 1.08–1.73), and vaginal delivery following successful ECV ($RR = 1.21$, 95% CI, 1.04–1.41). There is currently insufficient data to evaluate the effectiveness of neuraxial analgesia without tocolysis or to favor either spinal or epidural analgesia over the other. Neuraxial analgesia, when used in conjunction with tocolytic therapy, can be considered to enhance ECV success.

Standard Protocol

Prior to performing ECV, ultrasound is utilized to confirm fetal malpresentation and to rule out any anomalies that might complicate vaginal delivery. Informed consent is essential and should include a discussion of the risks and benefits associated with the procedure, tocolysis, and neuraxial analgesia. Fetal well-being and contraction patterns should be evaluated using a nonstress test or biophysical profile both before and after the procedure (see Fig. 1).

ECV should only be attempted in settings where cesarean delivery services are immediately available. A common technique involves lifting the breech upward from the pelvis with one hand while applying pressure to the fetal head with the other. Intermittent ultrasonography is helpful for monitoring fetal heart rate and position throughout the procedure. The ECV attempt should be discontinued if there is prolonged fetal bradycardia or significant discomfort reported by the patient.

Following the ECV attempt, a repeat fetal evaluation is performed, and the patient is monitored for a minimum of 30 minutes, or longer if clinically indicated. Anti-D immune globulin is administered to Rh-negative patients if delivery is not anticipated within the next 72 hours. There is no current evidence to support immediate induction of labor to minimize the risk of reversion.

Cost Implications

A decision analysis has determined that ECV results in fewer cesarean births and lower overall costs compared to either scheduled cesarean delivery or trial of labor without ECV. Even when ECV attempts are unsuccessful and followed by routine cesarean delivery, the overall cesarean birth rate remains lower than with trial of labor alone. As long as less than 52% of breech presentations meet the criteria for a trial of labor, attempting ECV is more cost-effective than proceeding directly to routine cesarean delivery or trial of labor without ECV.

Another computer-based model, which incorporated hospital costs and quality-adjusted life years, was used to assess the cost-effectiveness of ECV. The analysis indicated that ECV is cost-effective when the probability of success exceeds 32%. A decision-analysis model also found that the use of neuraxial analgesia with ECV resulted in cost savings when the ECV success rate surpassed 48% and 44% from the perspectives of the hospital and healthcare insurance payor, respectively. However, Monte Carlo simulation demonstrated this outcome in fewer than half of the scenarios considered. It is important to note that only direct medical costs were included in these analyses, excluding indirect costs, quality-adjusted life years, and potential effects on future pregnancies.

Summary of Recommendations

Level A Recommendation

Given the minimal risk of adverse events associated with ECV and the significant reduction in cesarean birth rates among women who have undergone successful ECV, all near-term women with breech presentations should be offered an ECV attempt, provided there are no contraindications.

Level B Recommendations

• Fetal presentation should be assessed and documented beginning at 36 0/7 weeks of gestation to allow for consideration of ECV.

• Current evidence supports the use of parenteral tocolysis to improve the success of ECV procedures.

• The use of neuraxial analgesia in combination with tocolytic therapy can be considered a reasonable intervention to increase the ECV success rate.

Level C Recommendations

• Fetal well-being and contraction patterns should be assessed using a nonstress test or biophysical profile before and after the ECV procedure.

• External cephalic version should only be attempted in settings where cesarean delivery services are readily available.