What are the pros and cons of external cephalic version (ECV) for a breech fetus?

External Cephalic Version for Breech Presentation

External cephalic version (ECV) should be offered to women with breech presentation at 36-37 weeks of gestation, as it substantially reduces cesarean delivery rates with minimal risk when performed with tocolysis and proper monitoring.

Major Advantages of ECV

Reduction in Cesarean Delivery

• ECV reduces cesarean section rates by approximately 15% when successful, with routine tocolysis decreasing version failure rates (relative risk 0.74,95% CI 0.64-0.87) and reducing cesarean sections overall (relative risk 0.85,95% CI 0.72-0.99) 1
• Success rates range from 62-75% at term, with higher success rates (approximately 79-81%) when performed before 37 weeks compared to 53% at or after 37 weeks 2, 3, 4
• After successful ECV, 56-72% of women achieve vaginal delivery, avoiding both the risks of breech delivery and cesarean morbidity 4, 5

Avoidance of Breech-Related Complications

• ECV prevents the substantial maternal morbidity associated with cesarean delivery for breech presentation, including impacted fetal head complications that occur in at least 5-10% of emergency cesarean deliveries 6, 7
• Impacted fetal head during cesarean can cause unintentional uterine incision extensions, hemorrhage, bladder and ureteric injuries, all of which are avoided when ECV successfully converts to cephalic presentation 6
• Successful version eliminates the need for complex delivery techniques like reverse breech extraction, which require specialized training many obstetricians lack 8

Improved Neonatal Outcomes

• Statistically significant decreases in clinically depressed and acidotic newborns have been documented after successful ECV compared to breech delivery 2
• No significant difference in APGAR scores between successful and unsuccessful ECV attempts, indicating the procedure itself does not harm the fetus when properly performed 5

Major Disadvantages and Risks of ECV

Failure Rates and Reversion

• 25-38% of ECV attempts fail, particularly with extended fetal legs, nulliparity, higher maternal body mass index, and attempts at or after 37 weeks 2, 3
• Even after successful version, approximately 1% of fetuses revert to breech presentation before delivery, though this rate is lower when performed closer to term 2

Periprocedural Complications

• Transient fetal bradycardia occurs in approximately 20% of cases (5 of 24 monitored cases in one series), typically resolving within minutes with maternal lateral positioning 2
• Emergency cesarean delivery may be required in approximately 1.5% of cases due to persistent fetal bradycardia or other acute complications 4, 5
• The procedure carries theoretical risks of placental abruption, cord entanglement, and fetomaternal hemorrhage, though these are rare with proper technique 2, 5

Technical Limitations

• ECV requires immediate access to emergency cesarean delivery capabilities, limiting its availability to hospital settings with appropriate resources 2
• The procedure is contraindicated in multiple gestations, placental abnormalities, ruptured membranes, and when cesarean delivery is already indicated for other reasons 2
• Success depends heavily on operator experience and proper use of tocolysis 1

Optimal Timing and Technique

Timing Considerations

• 37 weeks of gestation represents the optimal timing, balancing higher success rates (81% at 37 weeks) with fetal maturity for immediate delivery if complications arise 4
• Preterm ECV (before 37 weeks) has 27 times higher success rates than at or after 37 weeks, but carries the disadvantage of higher reversion rates and potential need for preterm delivery if complications occur 3

Essential Technical Elements

• Tocolysis with beta-agonists (20-50 micrograms Fenoterol IV) is essential, as it significantly improves success rates by relaxing the uterus 2, 1
• Ultrasound confirmation of fetal position before and after the procedure is mandatory 2
• Continuous cardiotocography immediately after version is required to detect transient bradycardia or other fetal compromise 2
• The technique involves positioning hands against the fetal forehead and turning the infant in a backward roll motion 2

Critical Pitfalls to Avoid

• Never attempt ECV without immediate access to emergency cesarean delivery, as persistent fetal bradycardia requiring emergency delivery occurs in 1-1.5% of cases 2, 5
• Do not perform ECV without tocolysis, as this substantially reduces success rates 1
• Avoid attempting version during uterine contractions, which decreases success and increases discomfort 2
• Do not proceed with ECV if extended fetal legs are present, as this significantly decreases success rates 2
• Never discharge the patient without confirming fetal well-being with cardiotocography for several minutes after the procedure 2

When ECV Fails or Is Contraindicated

• If ECV is unsuccessful or contraindicated, cesarean delivery is the most common and safest approach in settings where expertise for vaginal breech delivery is unavailable 6
• Vaginal breech delivery can only be considered when the provider has appropriate expertise, no contraindications exist, and proper facilities for emergency cesarean are immediately available 6
• Prepare for potential impacted fetal head complications during cesarean, including having personnel trained in reverse breech extraction and manual disimpaction techniques 6, 8