When healthcare providers look to prescribe a medication, ideally their decision is clear cut because ample clinical data exist in the relevant study populations. In reality, however, it is not uncommon that certain patient populations are not yet well captured. Deborah A. Komlos at Clarivate Analytics describes that this is the case for pregnant women, who usually are actively excluded from clinical trials. Actions by the US Food and Drug Administration (FDA) in recent years, including the issuance of new regulations and guidance documents, aim to remedy this shortcoming.