Flo, one of the most popular period tracking apps with more than 77 million monthly active users, continues to share users’ sensitive reproductive health data with third-party companies.
This raises serious privacy concerns for millions of women.
In an investigation conducted by the Mozilla Foundation and first shared by the BBC, the app sends users’ health information to data management companies, including RudderStack, which isn’t even named in Flo’s privacy policy.
The research found that Flo shared in-depth reproductive health data including:
- Pregnancy status
- Birth control methods
- Mood patterns
- Alcohol consumption
- Specific symptoms including stomach cramps
In response to the investigation, the company claims that this is only for “technical pipeline” purposes and that RudderStack is bound by a contract prohibiting it from selling the data.
This isn’t the first time Flo has been engaged in a privacy scandal. In 2021, the company settled with the US Federal Trade Commission over allegations it shared sensitive user information with Meta, Google, and others after promising to keep data private.
Earlier in August 2025, a federal jury found Meta liable for gathering the reproductive health data from Flo users through tracking tools that were built in the app between 2016 and 2019.
Privacy advocates warn that period-tracking data can be utilised in criminal cases.
