Cardiac drug use in pregnancy: safety, effectiveness and obstetric implications.

Morbidity and mortality due to cardiovascular disease is increasing in pregnancy. The physiologic changes of normal pregnancy serve as a 'stress test' on the cardiovascular system. This may lead to the unmasking of a latent underlying cardiac condition or the new onset of maternal cardiovascular disease, with an attendant increase in adverse maternal and fetal outcomes. Some women with pre-existing cardiac conditions may be receiving medications that need to be altered during pregnancy owing to a risk of adverse effects on the developing fetus, but for most cardiac conditions, there are safe and effective treatment options. Women should be educated that abrupt discontinuation of cardiac medications during pregnancy usually poses a greater risk than the medications themselves, and a plan of judicious drug selection should be implemented (ideally prior to conception).