Drug therapy during pregnancy is often associated with many concerns regarding fetal safety and maternal health. Yet, more often than not chronic or pregnancy induced diseases such as epilepsy, gestational diabetes, hypertension, infectious diseases and depression necessitate drug treatment during pregnancy. In fact, it is estimated that about 65% of pregnant women ingest at least one drug other then prenatal vitamin or mineral supplement while pregnant. As such better understanding of how pregnant women differ from nonpregnant women and men in how they respond to drugs and how their bodies handle drugs is critically important. In addition, for any drug that is consumed by the pregnant mother, the unborn fetus is also almost always also exposed to the drug. Yet, different drugs result in very different exposures to the fetus. At present there is considerable evidence that drug disposition and the kinetics of the sojourn of the drug in the body are altered during pregnancy in a gestational stage and drug dependent manner. Our research is focused on improving our understanding on how and by how much drug disposition is altered during pregnancy. We are working on characterizing the mechanisms that result altered expression and activity of drug metabolizing enzymes during pregnancy and on clinical studies of how drug disposition is affected by pregnancy. Our lab is also part of the “University of Washington Program on Pharmacokinetics of Drugs of Abuse During Pregnancy UWPKDAP” with emphasis on understanding how exposure to drugs used to treat addiction and to drugs of abuse is altered during pregnancy and to what magnitude the fetus is exposed to these drugs at different stages of pregnancy.