One-third of women with heart disease use medication for the treatment of cardiovascular disease (CVD) during pregnancy. Increased plasma volume, renal clearance, and liver enzyme activity in pregnant women change the pharmacokinetics of these drugs, often resulting in the need for an increased dose. Fetal well-being is a major concern among pregnant women. Fortunately, many drugs used to treat CVD can be used safely during pregnancy, with the exception of high-dose warfarin in the first trimester, angiotensin-converting-enzyme inhibitors, angiotensin-receptor blockers, amiodarone, and spironolactone. A timely and thorough discussion between the cardiologist and the pregnant patient about the potential benefits and adverse effects of medication for CVD is important. Noncompliance with necessary treatment for cardiovascular disorders endangers not only the mother, but also the fetus. This Review is an overview of the pharmacokinetic changes in medications for CVD during pregnancy and the safety of these drugs for the fetus. The implications for maternal treatment are discussed. The Review also includes a short section on the cardiovascular effects of medication used for obstetric indications.