In which heart disease is pregnancy an absolute contraindication?

Absolute Contraindications for Pregnancy in Heart Disease

Pregnancy is absolutely contraindicated in patients with pulmonary arterial hypertension of any cause, as it carries an extremely high risk of maternal mortality (40-100%) and should be absolutely avoided. 1

Conditions with Absolute Contraindication to Pregnancy (WHO Class IV)

The following heart conditions are classified as WHO risk class IV, where pregnancy is absolutely contraindicated:

1. Pulmonary arterial hypertension of any cause

   • Especially those with Eisenmenger physiology, with maternal mortality rates up to 50% 1
   • Even with modern vasomodulatory agents, pregnancy remains absolutely contraindicated due to unpredictable outcomes 1

2. Severe systemic ventricular dysfunction (LVEF <30%, NYHA III-IV) 1

3. Previous peripartum cardiomyopathy with any residual impairment of left ventricular function 1

4. Severe mitral stenosis and severe symptomatic aortic stenosis 1

5. Marfan syndrome with aorta dilated >45 mm 1

6. Aortic dilatation >50 mm in aortic disease associated with bicuspid aortic valve 1

7. Native severe coarctation of the aorta 1

Management of Women with Contraindicated Conditions

For women with conditions where pregnancy is absolutely contraindicated:

• Pre-conception counseling is essential to discuss the high risks of maternal mortality 1

• Effective contraception should be strongly advised 1

  • Single-barrier contraception alone is not recommended due to high failure rates 1
  • Estrogen-containing contraceptives should be avoided, especially in PAH 1
  • The levonorgestrel-releasing intrauterine device is considered the safest option for women with cyanotic heart disease and pulmonary vascular disease 1

• If pregnancy occurs despite counseling:

  • Early referral to a specialized center with multidisciplinary expertise is crucial 2
  • Earliest possible pregnancy termination should be recommended 1
  • First trimester termination is the safer option compared to later termination 1
  • Pregnancy termination in the last two trimesters carries high maternal risk but may be reasonable after balancing risks 1

Risk Assessment

The modified WHO classification system provides the most comprehensive approach to risk assessment:

• WHO Class IV (pregnancy contraindicated): 40-100% risk of maternal mortality 1
• WHO Class III (significantly increased risk): 19-27% risk 1
• WHO Class II-III (moderate risk): 10-19% risk 1
• WHO Class II (small increased risk): 5.7-10.5% risk 1
• WHO Class I (no detectable increased risk): 2.5-5% risk 1

Special Consideration: Pulmonary Arterial Hypertension

PAH deserves special attention as it represents the highest risk condition:

• Recent studies confirm maternal mortality rates of 28% even with modern multidisciplinary management 3
• NYHA functional class III-IV is a significant predictor of mortality 3
• Physiological changes of pregnancy exacerbate PAH, leading to right ventricular failure 2
• Despite recommendations against pregnancy, there is a growing incidence of pregnancy among women with PAH 2

Pitfalls and Caveats

1. Delayed diagnosis of heart disease during pregnancy significantly increases mortality risk 4

2. Anesthesia considerations are critical if delivery becomes necessary:

   • Regional anesthesia appears superior to general anesthesia for cesarean section 4
   • Higher mortality has been observed with general anesthesia 4

3. Postpartum period carries particularly high risk:

   • Maternal mortality may be especially increased in the first several days after delivery 1
   • Minimum 48 hours of monitoring is recommended 5

4. Surgical sterilization should be considered but carries operative risks:

   • Endoscopic sterilization may be the safer option 1
   • Benefits and risks should be discussed with experienced obstetricians and cardiac anesthesiologists 1

In conclusion, pulmonary arterial hypertension represents the most significant absolute contraindication to pregnancy due to extremely high maternal mortality risk, followed by other WHO class IV conditions that similarly pose unacceptable risks to the mother's life.