Pharmacology of Drug Transfer Across the Placenta

The fetus is exposed to the environment through interactions with the mother. The unique nature of the fetal habitat and the adaptations of the fetus to the intrauterine environment require that special attention be paid to fetal pharmacology. This review provides a basic framework for the clinician to evaluate fetal drug exposure and the likely consequences of such exposure using dose-response principles. The specific areas focused on are (1) the general mechanisms by which drugs administered to the mother exert their effect on the fetus, (2) how fetal drug exposure relates to maternal drug concentration, (3) placental permeability and mechanisms of placental transfer, and (4) the role of the fetus in determining fetal concentrations.