This qualitative study explores the experiences of women as they respond to, make sense of, and use uncertain health information mediated by informal and formal sources encountered with the context of everyday life. A medical case in which health information is explicitly evolving provides context for the investigation. Using a social constructionist approach and social positioning theory, and based on semi-structured interviews with both information seekers and health professionals, this study demonstrates that women participate in complex information worlds and that, in the face of uncertainty, are critically informed by a wide range of sources. Findings suggest that social positioning plays an important role in information behavior and in decision making, and that it is a dynamic construct which is influenced by personal context, the quality of relationships, and the experience of physical symptoms.