Recently, guidelines for antenatal management of depression were published.1 Psychotherapy alone may be an appropriate treatment for some women, while psychopharmacotherapy may be indicated in others. Use of psychopharmacotherapy during pregnancy and the postpartum involves complex clinical decisions based on the risks and benefits and alternatives to medications. The aim of effective treatment is to minimize maternal and fetal exposure to psychiatric illness by optimally treating it with the minimum effective dose regimen. One variable that complicates psychopharmacotherapy is that dosing often requires adjustment to maintain therapeutic effects, particularly in late pregnancy. The current article focuses on those factors that affect dosing in pregnancy.