The following are 10 points to remember regarding a recent review of pregnancy in women with congenital heart disease:

1. Normal physiologic changes of pregnancy include increased stroke volume, heart rate, and cardiac output, with a decrease in total peripheral resistance. Peak hemodynamic load is reached during the second trimester.
2. The modified World Health Organization (WHO) classification of maternal pregnancy risk is a useful tool in assessing pregnancy risk. WHO Class III defects are associated with a high risk of morbidity and increased risk of maternal mortality. Such diagnoses include mechanical heart valves, systemic right ventricle lesions, the Fontan palliation, unrepaired or palliated cyanotic lesions, Marfan syndrome with aorta <40 mm, severe systemic atrioventricular (AV) valve regurgitation, asymptomatic left ventricular outflow tract stenosis with gradient >50 mm Hg, left AV valve stenosis with valve area <2.0 cm², and systemic ventricular ejection fraction 30-40%.
3. WHO Class IV diagnoses (high maternal mortality with consensus that pregnancy should be discouraged) include severe symptomatic aortic valve stenosis, severe left AV valve stenosis, pulmonary hypertension, systemic ventricular ejection fraction <30%, New York Heart Association (NYHA) functional class III and IV, Marfan syndrome with aorta >45 mm, bicuspid aortic valve with aorta >50 mm, and severe coarctation of the aorta.
4. Prepregnancy evaluation should include review of all medications. A trial off of medications contraindicated in pregnancy should be considered prior to a decision to proceed with pregnancy.
5. Women should be counseled regarding fetal risks, including risk of miscarriage, prematurity, low birth weight, and risk for recurrence of congenital heart disease. The recurrence risk is specific to the type of maternal defect, but is on average approximately 3-5%.
6. There are little data regarding long-term cardiac outcomes after pregnancy for women with heart disease. There is an increased and unpredictable risk in patients following atrial switch procedures for decline in ventricular function, which does not recover after delivery.
7. There are two peaks for development of heart failure for women with congenital heart disease. The first is towards the end of the second trimester of pregnancy, coincident with that plateau of the hemodynamic load during pregnancy. The second peak occurs in the peri- and early postpartum period.
8. Women with mechanical heart valves are at high risk for thromboembolic events. Anticoagulation with vitamin K agonists is the safest for the mother. Offspring of women receiving a low dose of warfarin (<5 mg) have a low risk of embryopathy and fetal loss as compared with those requiring higher doses. Women receiving low molecular weight heparin during pregnancy should have close monitoring of anti-factor Xa levels.
9. Vaginal delivery is generally the preferred method of delivery for most women with congenital heart disease. A Caesarean section may be preferred in women with aortic diameter >45 mm, those with pre-term labor while anticoagulated, patients with symptomatic severe aortic stenosis, and those with severe heart failure.
10. A detailed, multidisciplinary delivery plan is an important part of the care of women with congenital heart disease during pregnancy. This plan should include description of the cardiac anatomy and hemodynamics, specific recommendations (including site of blood pressure measurement), anticipated complications, precautions for commonly used obstetric drugs, recommendation for mode of delivery, anesthetic plan, and detailed plan for postpartum care.

Keywords: Aortic Coarctation, Aortic Valve Stenosis, Blood Pressure, Cesarean Section, Constriction, Pathologic, Heart Defects, Congenital, Heart Failure, Heart Valve Diseases, Heparin, Low-Molecular-Weight, Hypertension, Pulmonary, Infant, Low Birth Weight, Marfan Syndrome, Postpartum Period, Pregnancy Trimester, Second, Stroke Volume, Vascular Resistance, Ventricular Function, Warfarin

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