Although most drugs are used to treat chronic or pregnancy-induced conditions during pregnancy and lactation, very few are studied in pregnant or breastfeeding women. The information we have on drugs taken during pregnancy and lactation is usually obtained after market approval through published case reports or case series and from pregnancy exposure or retrospective birth defect registries. Furthermore, generic drugs approved for use in this vulnerable population may be approved based on results from a male trial population. This disregards the changes that can occur during pregnancy which can affect the pharmacokinetics of drugs. In an effort to improve the information provided to prescribers, in 2008 the United States Food and Drug Administration proposed a change in product labelling where information from pregnancy exposure registries would be required. As of 2009, European Medicines Agency requires additional statements on use during pregnancy within drug labelling information. In Canada, it is anticipated that the efficacy and safety of drugs in pregnancy will be included under the Drug Safety and Effectiveness Network initiative, and that this will offer a unified approach for such assessments. Pregmedic, a non-profit organization for the advancement of safe and effective use of drugs in pregnancy, has presented a number of proposals and draft guidelines to Health Canada on the inclusion of pregnant women in pharmacokinetic studies and the establishment of registries for women who take drugs during pregnancy. Pregmedic advocates for ensuring that drugs indicated for women are studied in women.