Blood and Data Flows: Menstrual Cycle Tracking Technologies and the Production of Corporeal Experience and Gynecological Knowledge: This study examines menstrual cycle tracking applications (MCTAs) as emerging "cloud-based care infrastructures" (Langstrup, 2013) that integrate diverse personal data, from medical and physiological to lifestyle and social information. While menstrual tracking has existed before, digitization has transformed it, making users’ intimate data central to MCTA business models. Despite privacy concerns, users rely on these apps for insights into their bodies, managing fertility, health, and daily life. This research, drawing from feminist science and technology studies (STS), explores how MCTAs shape gendered bodily experiences, considering how users interpret app-generated data, balance it with bodily sensations, and navigate uncertainties—what Lomborg et al. (2020) term “data doubt.” Through the MenstruTECH project, this paper presents preliminary findings from document and interface analysis of MCTAs, online ethnography, interviews with 30 users, and a survey of 2,000 participants. Findings reveal significant variations in how users produce and use intimate data based on their health status and relationship with bodily experiences. Initial results indicate a need to connect sexuality education with digital literacy around platform economics, highlighting the interplay between data use, user privacy perceptions, and the material realities of the body, as argued by Wilson (2015) and Grosz (1994). | Synapse