- Period tracking apps vary in privacy practices, with some sharing user health data with third parties like Google, Meta, and TikTok.
- Stardust was found sharing detailed reproductive health data with RudderStack, though it claims data is anonymized and not misused.
- Euki is recommended for storing all health data on-device, allowing anonymity and offering a decoy feature for privacy.
- Flo and Clue scored well for transparency and controls but store health data on servers, raising breach or legal request risks.
- Past privacy scandals include Flo's FTC settlement and online sales of device lists from apps like Clue and Period Calendar.
- Experts warn that data from period trackers could be used in criminal cases post-abortion law changes, highlighting regulatory gaps in the U.S.