A new report by the Mozilla Foundation reveals that some period tracking apps share sensitive user health data with third parties, including companies like Google, Meta, and TikTok. While apps like Euki are praised for strong privacy protections, others like Stardust have been found to share detailed reproductive health information with data management companies without clear disclosure in their privacy policies.

Mozilla investigated six popular apps: Flo, Clue, Stardust, Spot On, Period Calendar, and Euki. The research highlights that while some apps are making efforts to improve privacy, significant risks remain, especially concerning the sharing of data that could identify users or reveal their health concerns. The sharing of even basic user information can have consequences, potentially alerting law enforcement to a trove of health data.

Euki stands out as the only app recommended without reservations, as it stores all health information locally on the user's device, enhancing anonymity and security. Flo and Clue offer transparency and privacy controls, but still collect extensive health data on their servers, posing potential risks of data breaches or legal requests. The report emphasizes the importance of user awareness regarding how their data is handled and the need for apps to prioritize privacy.