What are the contraindications for vaginal delivery?

Contraindications for Vaginal Delivery

Vaginal delivery is the preferred mode of delivery for most pregnant women, with cesarean section reserved primarily for specific obstetric indications and select high-risk maternal cardiac conditions that pose substantial mortality risk. 1

Absolute Contraindications to Vaginal Delivery

Maternal Cardiac Conditions

• Severe pulmonary arterial hypertension (PAH) and Eisenmenger syndrome represent absolute contraindications due to maternal mortality rates of 20-50%, with death occurring most often in the peri- or postpartum period 1, 2
• Acute or chronic aortic dissection requires cesarean delivery to avoid hemodynamic stress of labor 1
• Marfan syndrome with aortic diameter >45 mm should undergo cesarean delivery due to risk of aortic rupture 1
• Acute intractable heart failure necessitates cesarean delivery 1
• Severe symptomatic left ventricular outflow tract obstruction (LVOTO) is a contraindication for pregnancy itself and would require cesarean delivery if pregnancy occurs 1

Maternal Anticoagulation Status

• Patients on oral anticoagulants (OACs) in preterm labor should undergo cesarean delivery to minimize the period off anticoagulation and reduce risk of maternal valve thrombosis 1, 2
• Women with mechanical heart valve prostheses may require cesarean delivery when prolonged switch to heparin/LMWH would be required for vaginal birth, particularly when the obstetrical situation is unfavorable 1

Obstetric Contraindications

• Footling breech presentation is the only breech contraindication with universal consensus across all national guidelines 3
• Feto-pelvic disproportion is an absolute contraindication to vaginal breech delivery 4
• Hyperextension of the fetal head in breech presentation 4
• Umbilical cord presentation 4
• Fetal distress with irreversible causes including major placental abruption, fetal hemorrhage, and umbilical cord prolapse with sustained bradycardia 2

Relative Contraindications (Cesarean Delivery Should Be Considered)

Maternal Cardiac Conditions

• Severe aortic stenosis (AS) - cesarean delivery is advocated in some centers, though not universally agreed upon 1
• Marfan syndrome with aortic diameter 40-45 mm - cesarean delivery may be considered 1
• Cyanotic congenital heart disease with oxygen saturation <85% carries substantial maternal and fetal mortality risk; if pregnancy continues, mode of delivery should be individualized with planned cesarean or vaginal delivery favored over emergency cesarean 1

Obstetric Conditions

• Breech presentation with fetal weight <1500 g is a relative contraindication 4
• Premature rupture of membranes with unripe cervix in breech presentation 4

Infectious Disease Considerations

• HIV-1 RNA >1,000 copies/mL near delivery requires scheduled cesarean delivery at 38 completed weeks with intravenous zidovudine started at least 3 hours before surgery 2
• Hepatitis C with high viral load - cesarean may reduce vertical transmission risk 2

Important Clinical Nuances

Cardiovascular Disease Context

The ESC guidelines emphasize that vaginal delivery is associated with less blood loss, lower infection risk, and decreased risk of venous thrombosis and thromboembolism compared to cesarean delivery 1, 5. Even in patients with cyanotic congenital heart disease, vaginal delivery is advised in most cases unless maternal or fetal condition deteriorates 1.

Common Pitfalls to Avoid

• Do not perform cesarean delivery solely based on history of corrected congenital heart disease if the patient has good exercise tolerance, normal ventricular function, and good functional status 1
• Avoid dinoprostone for labor induction in active cardiovascular disease due to profound effects on blood pressure; mechanical methods like Foley catheter are preferable 1
• Emergency cesarean delivery carries higher risk than either planned cesarean or vaginal delivery in cardiac patients 1
• Inadequate multidisciplinary preparation in high-risk cases leads to poor outcomes; delivery should occur in tertiary centers with specialist team care 1, 2

Maternal Mortality Considerations

Maternal mortality is significantly increased with ERCD at 13.4 per 100,000 versus 3.8 per 100,000 for trial of labor, though both rates remain low 6. This mortality difference reinforces the preference for vaginal delivery when not contraindicated.