Scientifically rigorous efforts to monitor the potential negative effects of biopharmaceutical products are an important component of post-approval product safety. Such monitoring is critical. While the consequences of birth defects for children, their families, and society are potentially serious, the uncertainty and fear surrounding these risks can lead physicians and patients to withhold therapeutic interventions that are necessary to treat severe chronic conditions, and can also lead to unnecessary pregnancy terminations. ANDERSEN ROSS/GETTY IMAGES During the development process, regulatory agencies require all medicinal products to undergo pre-clinical testing to determine reproductive effects, but the results of these studies are not necessarily predictive of the human experience. Clinical trials exclude pregnant women; thus, little is known about the human teratogenic effect of a product at the time it first enters marketing. Once a drug is on the market, a spontaneous safety reporting system is in place to monitor all adverse drug reactions, including both normal and abnormal outcomes of pregnancy drug exposures. Healthcare providers and patients report adverse drug reactions to the manufacturer of the drug, and the manufacturer is required by law to report these events to regulatory agencies. This spontaneous reporting system is useful for identifying severe and unusual events. However, it is inadequate for monitoring the range of reproductive events that pregnant women exposed to the drug may experience.