The physiologic changes imposed by pregnancy can cause cardiac decompensation in patients with any significant cardiac abnormality, but the most severe problems are encountered in patients with valvular stenosis (especially mitral and aortic stenosis), congenital or acquired abnormalities associated with pulmonary hypertension or right-to-left shunting, heart failure due to any cause, and systemic hypertension. Valvular insufficiency or left-to-right shunting often diminishes because of the fall in peripheral resistance and is better tolerated than other lesions.
Coarctation of the aorta is usually well tolerated unless severe, when perfusion of the gravid uterus and upper extremity hypertension become an issue. Patients with symptoms or significant upper extremity hypertension before pregnancy should have corrective surgery before embarking on a pregnancy. Patients with severe pulmonary hypertension and cyanotic congenital heart disease and those with severe aortic stenosis are at extremely high risk and should avoid pregnancy. Balloon valvuloplasty of severe aortic stenosis is feasible and preferable to surgical intervention during pregnancy if possible. Patients with most right-sided lesions do well with pregnancy, including those with ASD, pulmonic stenosis, pulmonary valve regurgitation, operated tetralogy of Fallot, and Ebstein anomaly. Those with an RV that supports the systemic circulation can usually tolerate pregnancy unless symptomatic heart failure has already occurred. Most adult patients with a systemic RV have transposition of the great vessels that has been surgically corrected or the condition is congenitally corrected (L-transposition of the great vessels). Patients with hypertrophic cardiomyopathy also do well, though the risk of an adverse event in pregnancy is higher than normal. Patients with a Fontan can carry a pregnancy if no HF has occurred. Again, since the Fontan physiology is poorly tolerated long term, a discussion regarding having children at all is important so that the parents understand maternal cardiac deterioration may occur while the children are still young.
In Marfan syndrome, there are two issues, the risk of transmission of the genetic abnormality to the child and the risk of cardiovascular complications with pregnancy. Marfan patients tolerate pregnancy well if the aortic maximal diameter is 4.0 cm or less. Surgery before pregnancy should be considered if the aorta is greater than 4.0 cm. If the aorta is significantly dilated or there has been prior dissection, the pregnancy may precipitate aortic dissection. If the Marfan patient becomes pregnant, then physical activity should be limited and beta-blockers used throughout the pregnancy. Cesarean section is favored over vaginal delivery to avoid aortic pressure increases with bearing down.
Asymptomatic arrhythmias should be closely observed unless underlying heart disease is present, in which case they should be treated with appropriate medications. Amiodarone and dronedarone are contraindicated. Sotalol is first line for most of these. Paroxysmal supraventricular arrhythmias are quite common. Patients with Wolff–Parkinson–White syndrome may have more arrhythmias during pregnancy. Therapy is similar to that required for nonpregnant women. Preexisting systemic hypertension is usually well tolerated and controllable, though the fetal morbidity rate is slightly increased. The incidence of preeclampsia and eclampsia (see Chapter 19) is increased.
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et al. High-risk cardiac disease in pregnancy: part II. J Am Coll Cardiol. 2016 Aug 2;68(5):502–16.
et al. Pregnancy complicated by valvular heart disease: an update. J Am Heart Assoc. 2014 Jun 5;3(3):e000712.