Period tracker app privacy is a big deal — they hold a lot of sensitive information that can be leaked. Now UK advocacy group Privacy International discovered that several period cycle-tracking apps had been sharing sensitive user data with Facebook. They announced Monday that apps MIA Fem and Maya had shared user-logged contraception use, monthly periods, and menstruation symptoms with the social network.
Privacy International investigated other popular menstrual tracking apps, like Period Tracker by Leap Fitness Group, Period Tracker Flo by Flo Health, Period Tracker by Simple Design and Clue Period Tracker by Biowink, but did not find they had shared any data with Facebook.
Maya by Plackal Tech and MIA by Mobapp Development, however, have been sharing extensive amounts of private information with Facebook and other third parties. Tracking apps like Maya and MIA are popular ways to monitor menstruation, pregnancy, and sexual health — they’re even compatible with Apple and Fitbit watches.

Maya and MIA, according to Privacy International, have been downloaded millions of times. CNET reported that Plackal Tech, the company that runs Maya, has removed the Facebook’s “core software development kit” from the app. However, Maya’s CEO John Paul told CNET that all the data Maya accesses is essential for its function.
“Location information, the significance of which is highlighted in the report, helps us triangulate regional variations in cycle lengths and thus help improve accuracy of our prediction over time. We will continue evaluating our privacy policy and align ourselves to global best practices on data privacy,” Paul said in an email.
Facebook can gather information from third-party apps to provide analytics or let users log in with Facebook, according to its terms of service. But Facebook officials claim this information is never used against members on the platform, or used to target ads. “Our terms of service prohibit developers from sending us sensitive health information… ad targeting based on people’s interests does not leverage information gleaned from people’s activity across other apps or websites,” Facebook spokesperson Joe Osborne told CNET.