Assessing, communicating, and managing risk are among the most challenging tasks in the practice of medicine and are particularly difficult in the context of pregnancy. We analyze common scenarios in medical decision making around pregnancy, from reproductive health policy and clinical care to research protections. We describe three tendencies in these scenarios: 1) to consider the probabilities of undesirable outcomes alone, in isolation from women's values and social contexts, as determinative of individual clinical decisions and health policy; 2) to regard any risk to the fetus, including incremental risks that would in other contexts be regarded as acceptable, as trumping considerations that may be substantially more important to the wellbeing of the pregnant woman; and 3) to focus on the risks associated with undertaking medical interventions during pregnancy to the exclusion of demonstrable risks to both woman and fetus of failing to intervene. These tendencies in the perception, communication, and management of risk can lead to care that is neither evidence-based nor patient-centered, often to the detriment of both women and infants.