Information on the safety of medications that pregnant women may need is key to protecting the health of the woman and her fetus. When new drugs are first marketed, this information is scarce, because pregnant women are generally excluded from randomized clinical trials. Broader inclusion of pregnant women in clinical research is being discussed by regulatory authorities and funders. But even with greater inclusion of pregnant women in clinical trials, safety data from those trials would be limited by the combination of study size, low frequency of many key outcomes, and strict conditions for enrollment. Postapproval observational studies still would be needed to assess drug safety in routine health care. These assessments can be conducted as pregnancy exposure registries or by using existing health databases. Currently, because of our overreliance on pregnancy exposure registries and underuse of database studies, we are missing an opportunity to provide information that would help women and their physicians make better informed decisions about treatment in pregnancy.
