Abstract
Patients' online information-seeking and sharing has sparked worries about medical misinformation and declining trust in biomedical professionals. At the same time, scholars advocate for including patients as knowers in the clinical encounter. Yet we lack empirical insights into the differing ways care providers and patients substantiate health-related knowledge. This article thus examines (1) how both groups substantiate claims about contraceptive side-effects, (2) the ways their substantiation processes differ and (3) how we can navigate this epistemic tension in contraceptive care. I draw on data from nine interviews with Dutch contraceptive care providers (one nurse practitioner, one gynaecologist and seven general practitioners) and 17 contraceptive users, observations of 11 contraceptive consultations in the Netherlands and analysis of Dutch clinical guidelines. Results reveal that patients substantiate their claims through combining embodied modes of knowing with self-experimentation as well as validation through social media exchanges. Care providers switch between two complementary approaches: demarcating biomedical knowledge from non-scientific claims and clinical tinkering. I show that epistemic tensions between provider and patient may arise because the two groups have differing definitions of what a side-effect is and differing evaluations of information shared online. Based on these findings, I argue that care providers invalidating information shared online may contribute to patients' growing distrust in biomedical authority while collaborative tinkering may provide a common ground for care providers and patients to co-create knowledge.