Principles of Pharmacokinetics in the Pregnant Woman and Fetus

Pregnancy profoundly alters a woman's physiology. These changes alter drug absorption, distribution, metabolism, and elimination and emphasize the pharmacologic complexity of pregnancy. They also emphasize the dangers of extrapolating pharmacologic expectations from nonpregnant populations to pregnant women and their fetuses. Although concerns about fetal safety have historically limited pharmacokinetic studies during pregnancy, it is important to recognize that many medications are clinically indicated for various maternal or fetal conditions, and it is particularly important that these therapies be evidence-based with appropriate study, including short-term and long-term outcomes data.