Overall, 5% of maternal deaths are due to heart disease. Most heart disease complicating pregnancy in the United States is congenital heart disease. Normal pregnancy causes a faster pulse, an increase of cardiac output of more than 30%, and a rise in plasma volume greater than red cell mass with relative hemodilution. Vital capacity and oxygen consumption rise only slightly.
For practical purposes, the functional capacity of the heart is the best single measurement of cardiopulmonary status.
In general, patients with class I or class II functional disability (80% of pregnant women with heart disease) do well obstetrically, with four-fifths of maternal deaths due to heart disease occurring in women with class III or class IV disability. Congestive failure is the usual cause of death. Most deaths occur in the early puerperium. Pregnancy is contraindicated in Eisenmenger’s complex, in Primary pulmonary hypertension, in severe mitral stenosis with secondary pulmonary hypertension, and in Marfan’s syndrome, in which the aorta is prone to dissection and rupture. In addition, pregnancy is poorly tolerated in patients with aortic stenosis, aortic coarctation, tetralogy of Fallot, and active rheumatic carditis.
Therapeutic abortion and elective sterilization should be offered to patients with significant cardiac disease. Cesarean section should be performed only for obstetric indications. Women with valvular heart disease, mitral valve prolapse associated with mitral insufficiency, or idiopathic hypertrophic cardiomyopathy should receive appropriate antibiotic prophylaxis against infective endocarditis during labor and delivery or termination of pregnancy.
Lupton M et al: Cardiac disease in pregnancy. Curr Opin Obstet Gynecol 2002;14:137.
Sadler L et al: Pregnancy outcomes and cardiac complications in women with mechanical bioprosthetic and homograft valves. Br J Obstet Gynaecol 2000;107:245.
FUNCTIONAL CARDIAC ASSESSMENT
Class I Ordinary physical activity causes no discomfort (perinatal mortality rate about 5%). Class II Ordinary activity causes discomfort and slight disability (perinatal mortality rate 10-15%). Class III Less than ordinary activity causes discomfort or disability; patient is barely compensated (perinatal mortality rate about 35%). Class IV Patient decompensated; any physical activity causes acute distress (perinatal mortality rate over 50%).
Revision date: July 8, 2011
Last revised: by David A. Scott, M.D.