During a summer internship at Metrum Research Group, I worked with a team of interns to develop a physiologically based pharmacokinetic (PBPK) model for maternal and fetal drug disposition throughout pregnancy. By integrating published data from studies in non-pregnant women with prior knowledge of anatomical, physiological, and biochemical changes associated with pregnancy, we were able to predict drug exposures in a population with limited experimental data. The resulting model can guide dosing prior to drug administration and refine dosing once initial exposures are determined.