Pregnancy is a frequently applied exclusion criteria for many forms of research. Common justifications for this exclusion include the potential for teratogenicity, as well as the potential for physiologic changes in pregnancy to impact the research itself. The systematic exclusion of pregnant persons from clinical studies has created a significant gap in knowledge regarding medication safety and efficacy in pregnancy, which continues to cause significant harm to pregnant persons in need of medical therapy. To produce meaningful data and facilitate effective knowledge translation to the clinical setting, special consideration to the pharmacology of pregnancy, as well as to outcomes of concern for this population is essential. The exclusion of pregnant participants from research is not ethically justifiable, as it violates the principles of autonomy, justice and nonmaleficence. While the inclusion of pregnant patients in research presents it's own challenges, with appropriate methodological, ethical, and clinical considerations, we may be able to narrow the knowledge gap and improve drug availability and safety for pregnant patients and their children.