Maternal adaptation to pregnancy includes reproductive hormone interaction plasma, volume changes with an increase in total body water, vascular alterations with a decrease in systemic resistance and modifications associated with hypercoagulability. These explain, in part, the appearance of signs and symptoms, even in a normal pregnant woman, that are difficult to distinguish from those occurring in heart disease and why some cardiac abnormalities are not well tolerated during pregnancy. Cardiovascular abnormalities are considered the first non-obstetric cause of morbidity and mortality during pregnancy. Rheumatic and congenital heart diseases are currently the most frequent cardiopathy found in women of childbearing age, followed by hypertension, coronary artery disease and arrhythmia. Although pregnancy is well tolerated by most women with heart disease, there are some cardiovascular abnormalities which place the mother and the infant at extremely high risk: patients with congestive heart failure and severe cardiac dysfunction, pulmonary hypertension, cyanotic congenital heart disease, Marfan's syndrome, severe obstructive lesions of the left side of the heart, patients with prosthetic cardiac valves and antecedents of peripartum cardiomyopathy should be encouraged to avoid pregnancy and the interruption of pregnancy may be advisable in cases with great risk of disability or death. The most severe cardiopathies significantly increase the risk of fetal loss and the presence of a congenital cardiac abnormality in either parent increases the risk of congenital cardiac disease in the fetus. Medical care must be initiated early, prior to conception and women with cardiopathy should be informed of the possible risks of pregnancy to both the mother and fetus.