The document discusses heart diseases that can occur during pregnancy. Some key points: - The incidence of heart disease during pregnancy is around 1%, which can be either congenital or acquired. The most common acquired heart diseases in developing countries are rheumatic heart disease, cardiomyopathies, and ischemic heart disease. - The most common cardiac lesions seen in pregnancy are mitral stenosis, atrial septal defects, and tetralogy of Fallot. The risks of cardiac decompensation are highest from 12-16 weeks, 28-32 weeks, during labor and delivery, and immediately following delivery. - Pregnancy causes an increase in cardiac output, blood volume, and a decrease in systemic and pulmonary