Most women of reproductive age use highly effective contraception and all available methods are associated with side effects. Whether a woman will experience side effects is uncertain, however, which can pose challenges for clinicians who discuss the methods with patients. In this study, we analyze 102 contraceptive counseling visits to understand how clinicians discursively construct knowledge in the context of uncertainty. We find that while some present the uncertainty of side effects in a straightforward, patient-accessible way, others negotiate their predictions by: 1) differentially constructing uncertainty, suggesting that positive side effects are likely and negative side effects are unlikely and, 2) contesting uncertainty, presenting the risk of serious side effects as controllable. In the end, these strategies deemphasize consideration of negative side effects in women’s contraceptive decision-making. Our results demonstrate the importance of elucidating the translation, instantiation, and construction of medical uncertainty—both in theory and in practice.