What are the recommended management and anatomical considerations for a breech presentation at 36 weeks?

Management of Breech Presentation at 36 Weeks: Anatomical Considerations and Delivery Planning

For breech presentation at 36 weeks, offer external cephalic version (ECV) as the primary intervention to reduce cesarean delivery rates, and if unsuccessful or contraindicated, plan for cesarean delivery with specific preparation for potential complications including impacted fetal head and reverse breech extraction techniques. 1

Impact on Maternal Anatomical Adaptations

Breech presentation itself does not fundamentally alter the normal maternal anatomical adaptations of pregnancy. However, the delivery planning requires specific anatomical considerations that differ substantially from cephalic presentation 1:

Key Anatomical Differences for Delivery

• The presenting part (buttocks or feet) does not mold or flex the cervix in the same manner as a fetal head, which can affect cervical dilation patterns and lower uterine segment development 2

• The lower uterine segment may be less well-developed compared to cephalic presentations, particularly if the breech remains high, increasing risk of uterine incision complications during cesarean delivery 2

• Pelvic architecture assessment becomes critical - the maternal pelvis must accommodate not just the presenting breech but ultimately the larger, less compressible fetal head as the aftercoming part 1

Primary Management: External Cephalic Version

Attempt ECV at 36-37 weeks as the first-line intervention to convert breech to cephalic presentation 3, 4:

• Success rates range from 47.8% to 64%, with the procedure significantly reducing cesarean delivery rates 3, 5

• ECV at 34-36 weeks may be more successful than waiting until 37-38 weeks (56.9% vs 66.4% noncephalic at birth), though this requires confirmation in larger trials 4

• Complications are rare (0.8-1.5%) and include placental abruption, abnormal fetal heart rate requiring emergency cesarean, and spontaneous rupture of membranes 3, 5

• Prior cesarean delivery is not a contraindication - ECV success rates of 50-100% are reported with no cases of uterine rupture in systematic reviews 6

• Use tocolytics and consider epidural analgesia to optimize success rates 4

Anatomical Considerations for Cesarean Delivery Planning

When ECV fails or is contraindicated, cesarean delivery is the most common approach and requires specific anatomical preparation 1:

Critical Anatomical Risks

The primary anatomical concern is impacted fetal head during cesarean delivery, which occurs in at least 5% of cesarean deliveries, particularly at full dilation 2:

• Impaction creates lack of space between the fetal head and maternal pubic symphysis, making standard delivery techniques impossible 2

• Risk of unintentional uterine incision extension increases significantly - extensions can tear laterally into uterine arteries and venous plexuses, or inferiorly into cervical arteries and vaginal plexuses 2

• Hemorrhage, bladder injury, and ureteric injury risks are substantially elevated with impacted head scenarios 2, 1

Specific Delivery Techniques for Breech Cesarean

Prepare for reverse breech extraction as the primary technique if standard delivery fails 2:

• Reverse breech extraction involves grasping one or both fetal feet and delivering the baby feet-first (similar to assisted vaginal breech delivery), then lifting the head out of the pelvis 2

• This "pull" technique may be safer than vaginal "push" disimpaction methods, with some evidence suggesting better neonatal outcomes including improved Apgar scores and reduced NICU admissions 2, 7

• The Patwardhan method (delivering arms first, then body) is an alternative but requires specialist training and is less commonly practiced outside specific regions 2

Prevention Strategies Before Uterine Incision

Consider manual vaginal disimpaction or Fetal Pillow device before making the uterine incision to elevate the fetal head and reduce impaction risk 2:

• The Fetal Pillow (inflatable vaginal device) may reduce uterine incision extensions (OR 0.50,95% CI 0.3-0.9) and decrease incision-to-delivery interval by approximately 52 seconds 2

• Evidence on Fetal Pillow effectiveness is mixed - some studies show benefit while larger observational studies show no significant maternal outcome improvement 2

Management of Impacted Head During Surgery

If impaction occurs despite preventive measures 2:

• Administer tocolysis immediately to relax the uterus and facilitate disimpaction techniques 2

• Avoid attempting delivery during uterine contractions, which exacerbates impaction 2

• Use proper technique for vaginal disimpaction - cup the entire fetal head with the whole hand (not 2-3 fingers) to avoid skull fracture risk and ensure adequate flexion 2

Vaginal Breech Delivery Considerations

Vaginal breech delivery can be considered only if the provider has appropriate expertise, no contraindications exist, and facilities for emergency cesarean are immediately available 1:

• This option is rarely pursued in current practice due to limited provider expertise and training 1, 7

• Continuous electronic fetal heart rate monitoring is mandatory during any attempted vaginal breech delivery 2, 8

Labor and Delivery Positioning

Position the woman in lateral decubitus during labor to minimize hemodynamic stress from uterine contractions 2, 8:

• Allow passive descent without active maternal pushing to avoid adverse Valsalva effects 2, 8

• Epidural analgesia reduces pain-related sympathetic activity and decreases premature pushing urges 2, 8

Post-Delivery Hemorrhage Prevention

Administer slow IV oxytocin infusion (<2 U/min) after placental delivery to prevent hemorrhage while avoiding dangerous hypotension 2, 8:

• Avoid rapid oxytocin bolus due to severe hypotension risk 2, 8

• Prostaglandin F analogues are useful for post-partum hemorrhage unless pulmonary artery pressure elevation is concerning 2

• Methylergonovine is contraindicated due to >10% risk of vasoconstriction and hypertension 2

Critical Pitfalls to Avoid

• Never attempt vaginal disimpaction with only 2-3 fingers - this increases fetal skull fracture risk and is ineffective 2

• Do not apply pressure on the uterine lower segment or angles during abdominal disimpaction - this causes dangerous lateral or inferior extensions 2

• Ensure obstetricians are trained in reverse breech extraction techniques before encountering impacted head scenarios, as many lack adequate training 7

• Continue hemodynamic monitoring for at least 24 hours post-delivery due to significant fluid shifts that may precipitate heart failure in women with structural heart disease 2