Perspective:

The following are 10 points to remember about pregnancy in patients with pre-existing cardiac disease:

1. Normal hemodynamic changes in pregnancy include increased circulating blood volume, increased cardiac stroke volume, and increased heart rate. The overall increase in cardiac output peaks between the second and third trimester.

2. The placental circulation provides a substantial reduction in systemic vascular resistance, particularly until the 32nd week of pregnancy, when afterload begins to rise again.

3. The peripartum period is associated with significant and rapid hemodynamic changes. During labor and delivery, cardiac output can increase by 30-50%. The average blood loss for a vaginal delivery is 500 ml, whereas the average blood loss for a routine C-section is 1000 ml.

4. Women with pre-existing cardiac disease should undergo a thorough preconception evaluation, including history to assess cardiac symptomatology, and appropriate imaging and functional testing.

5. Preconception counseling should include an assessment of the risk of transmission of cardiac disease to one’s offspring. This is particularly important for autosomal dominant processes, including Marfan syndrome, 22q11 deletion, and hypertrophic cardiomyopathy.

6. Women with potentially prohibitively high risk for pregnancy include those with mechanical heart valves, Eisenmenger syndrome, Marfan syndrome, and systemic ventricular ejection fraction <40%.

7. Risk scores have been developed to predict risk for cardiac complications in women with pre-existing heart disease. Generic risk factors include prior cardiac events, prior arrhythmias, New York Heart Association functional class III or IV, cyanosis, left ventricular outflow tract obstruction, and systemic ventricular ejection fraction <40%. A woman with >1 risk factor has a 75% risk of cardiac complication during pregnancy.

8. An individualized approach to contraception should be applied to women with heart disease. Estrogen-containing contraceptives may not be appropriate for patients at increased risk for thromboembolic events.

9. A majority of women with heart disease are candidates for vaginal delivery. C-section should generally be reserved for obstetric indications.

10. Most women with hypertrophic cardiomyopathy tolerate pregnancy reasonably well, although patients with cardiac symptoms prior to pregnancy and those with severe left ventricular outflow tract obstruction appear to be at increased risk for cardiac decompensation or sudden death. Beta-blockers may have an important role in management during labor and delivery, as they blunt the normal increases in heart rate and contractility that occur during labor.