Fetal risks of maternal pharmacotherapy: identifying signals.

Pregnant women may be exposed to a variety of medications that may exert toxic or teratogenic effects on the fetus. Since the thalidomide disaster, physicians and pregnant women tend to withhold medications during pregnancy, although the risk of teratogenic effect from most drugs in therapeutic doses is nonexistent. This chapter will review the principles of teratology and the pharmacoepidemiological evidence for drug safety/risk in human gestation.