Biosensing technologies are increasingly present, predicting bodily or emotional health and offering promises of improved efficiency or personal wellness. Menstrual tracking apps, for example, encourage users to report intimate details, from the duration of periods, cervical mucus texture, emotional state, to sexual behavior. These apps offer benefits but also pose risks in the case of a security breach or as practices of sharing health data become more prominent in the workplace. This project will conduct a review of existing menstrual biosensing technologies, their data policies, and users existing data practices to outline this rapidly shifting field. The project has potential to help users protect their intimate data privacy, and rethink assumptions of how these apps configure their users.