What are the considerations for an external cephalic version (ECV) procedure in a low-risk pregnant woman in her third trimester with a fetus in a breech position?

External Cephalic Version (ECV) for Breech Presentation at Term

Primary Recommendation

All women with a singleton breech presentation at term should be offered external cephalic version (ECV) from 36-37 weeks gestation, as this procedure significantly reduces breech presentation at birth and potentially lowers cesarean section rates without increasing serious maternal or perinatal morbidity. 1

Timing and Patient Selection

Optimal Gestational Age

• Perform ECV from 36 weeks gestation onward 1
• ECV before 37 weeks increases the rate of cephalic presentation at birth but carries a small increased risk of moderate prematurity 1
• The procedure can be safely performed at or after 37 weeks with high success rates 2

Predictors of Success

• Multiparity is the strongest predictor of successful ECV (success rates approximately 80% in multiparous women) 3, 2
• Flexed breech presentation (frank breech) is associated with higher success rates 2
• Non-engagement of the breech in the pelvis predicts success; engagement reliably predicts failure 3
• Maternal obesity is associated with lower success rates 1
• Placental location and birth weight show variable predictive value 2

Absolute Contraindications

Do not attempt ECV in the following circumstances:

• Multiple pregnancy 4
• Significant third-trimester bleeding 4
• Uteroplacental insufficiency or intrauterine growth restriction 4
• Oligohydramnios (the only contraindication mentioned in all major guidelines) 5
• Premature rupture of membranes 4
• Pregnancy-induced hypertension 4
• Non-reassuring fetal heart rate patterns 4
• Any absolute contraindication to vaginal delivery 4

Important Caveat on Contraindications

• There is no general consensus on ECV eligibility criteria across guidelines, with only oligohydramnios consistently listed as a contraindication 5
• Most stated contraindications lack empirical evidence and should be limited to those with clear pathophysiological relevance 5

Procedural Requirements and Safety

Mandatory Safety Protocols

• Perform ECV only with immediate access to an operating room for emergency cesarean section 1
• Conduct cardiotocography for 30 minutes before and after the procedure 1
• Delayed cardiotocography after ECV is not recommended 1

Tocolysis Administration

• Use parenteral tocolysis (β-mimetics or atosiban) for all ECV attempts at term 1
• Subcutaneous terbutaline sulfate 0.25 mg makes the procedure easier for both patient and operator 3
• Tocolysis increases success rates, cephalic presentation rates in labor, and decreases cesarean section rates 1

Rh Prophylaxis

• Administer 300 mcg Rh immune globulin to all Rh-negative women 3
• Routine Kleihauer testing after ECV is not recommended, as the risk of significant fetomaternal hemorrhage (>30 mL) is very low (<0.1%) 1

Technique

Standard Approach

• Use a single-operator, head-over-heels technique 3
• Position the patient in supine Trendelenburg position to assist with disengagement 3
• Perform under real-time ultrasound guidance 3
• Allow multiple gentle attempts rather than forceful manipulation 2

Expected Outcomes

Success Rates

• Overall success rate: 62.5-80% depending on patient selection 3, 2
• 98% of successfully verted fetuses remain cephalic and deliver in cephalic presentation 3

Impact on Cesarean Section Rates

• Cesarean section rate after successful ECV: 9.8-12.5% for routine obstetrical indications 3, 2
• In contrast, 50% of ECV failure patients require cesarean section despite liberal policies toward vaginal breech trials 3

Complications and Risks

Maternal and Fetal Safety

• ECV is not associated with increased severe maternal or perinatal morbidity 1
• Transient fetal heart rate abnormalities occur but are typically benign 1
• Risk of serious complications requiring urgent cesarean section: 1-3% 4
• Risk of intrauterine fetal death after ECV: 0.0001% (extremely rare) 4

Rare Complications

• One case of compound presentation at term resulting in dystocia and cesarean section has been attributed to prior successful version 3
• The most serious fetal complications in breech series occur with vaginal breech delivery, not ECV 3

Ineffective Alternative Methods

Do not recommend the following interventions, as they are ineffective:

• Acupuncture 1
• Moxibustion 1
• Postural methods 1

These methods do not reduce breech presentation at birth and should not be offered 1

Clinical Context

Why ECV Matters

• Prenatal mortality and serious complications after vaginal breech birth: 5% 4
• Prenatal mortality and serious complications after planned cesarean section for breech: 1.6% 4
• ECV provides a safe alternative that avoids both the risks of vaginal breech delivery and the maternal morbidity of cesarean section 2

Realistic Impact on Overall Cesarean Rates

• ECV is unlikely to significantly impact overall cesarean section rates in North America, as prematurity remains the greatest risk factor in malpresentation 3
• However, ECV deserves serious consideration as it avoids the costs and risks of either cesarean section or vaginal breech trial when successful 3