Mozilla’s latest privacy assessment of six popular period trackers disclosed major discrepancies in how these apps handle sensitive reproductive health information, with some sharing data with third-party analytics firms and others securing user data strictly on-device.
- Euki received a perfect privacy rating for local data storage.
- Stardust and other trackers share sensitive data with analytics companies.
- Mozilla's findings emphasize the importance of scrutinizing app privacy beyond marketing.
What happened
Mozilla joined forces with researchers from Harvard’s Berkman Klein Center and the University of Illinois to rigorously evaluate the privacy practices of six popular period tracking apps. The investigation involved analyzing privacy policies and conducting technical tests to track how user data was collected, stored, and shared.
Their findings exposed a significant gap in privacy protection: while one app, Euki, kept user data confined to the device itself, others including Stardust were found to transmit sensitive reproductive health information to third-party analytics services such as RudderStack, raising concerns about potential exposure of deeply personal data.
Why it matters
Reproductive health data is among the most sensitive types of personal information, and how this data is managed carries profound privacy implications, especially in light of heightened scrutiny after the U.S. Supreme Court’s decision overturning Roe v. Wade. Users of period trackers need assurance that their information remains confidential and protected from unwanted surveillance or data monetization.
Mozilla’s report illuminates the risk that popular apps may not deliver on their privacy promises, potentially exposing users to data profiling or third-party tracking without their explicit knowledge. This matters both for user trust and for setting standards in digital health privacy.
What to watch next
Consumers should critically evaluate the privacy claims of health tracking apps and prioritize those with transparency and strong data protections, like Euki, especially as legislative environments around reproductive health continue to evolve. Awareness of how apps handle sensitive data is crucial for informed decision-making.
Industry observers and privacy advocates will be looking to see how app developers respond to such reports, whether by improving privacy designs or offering clearer user control over data sharing. Regulatory scrutiny may also increase around these apps to ensure stronger protections for users’ reproductive health information.