Cardiac disease complicates more than 1% of pregnancies in the US and causes 20% of non-obstetrical deaths. The increase of heart disease in pregnancy is attributed to increased rates of obesity, hypertension and diabetes, in addition to the survival of women with congenital heart disease to maternal age. Furthermore, women are increasingly postponing pregnancy until the fourth decade of life. These factors increase the incidence of cardiac disease complicating pregnancy. In developed countries, cardiomyopathies, structural heart diseases, pulmonary hypertension, acute myocardial infarction and conduction abnormalities are the leading cardiac causes of maternal mortality.
The physiologic changes that occur during pregnancy lead to increases in preload, cardiac output, blood volume and oxygen consumption. Such changes can unmask, worsen or induce cardiac dysfunction. The diagnosis of cardiac decompensation is often difficult to make because complaints of shortness of breath, peripheral edema and chest pain can be attributed to normal pregnancy. The times of greatest risk for cardiac disease during pregnancy are the third trimester, peripartum and immediate postpartum periods.