On this episode of Prognosis, we'll meet the Bloody Health collective – a group of feminist coders in Berlin who are looking for a safer way to track their periods. Targeted advertising, third-party data sharing and tracking make most menstruation apps just as problematic as they are popular, privacy activists argue. For the women of Bloody Health, the sure way to keep control is to build their own open-source app.See omnystudio.com/listener for privacy information.