Privacy Study Reveals How Menstrual Tracking Apps Handle User Data
A study conducted by Mozilla found that several menstrual cycle tracking applications transmit user data to advertising firms and major platforms like Google, Meta, and TikTok. The worst performer was the Stardust app, which sends detailed reproductive health information to a third-party company called RudderStack. This investigation has become especially relevant in the United States following the 2022 rollback of federal abortion rights protections.
Six Cycle Trackers Put to the Test
The research examined six popular cycle trackers: Flo, Clue, Stardust, Spot On, Period Calendar, and Euki. Notably, Stardust shares data on pregnancy, contraception, mood, alcohol use, and symptoms—yet its privacy policy makes no mention of sharing data with RudderStack. The Spot On app, developed by Planned Parenthood, also raises red flags: its website transmits information about users searching for medical help to the analytics company AB Tasty, as well as to Google, Microsoft, TikTok, and Pinterest, with no option to opt out.
According to the findings, most of these apps send basic information to Google, Meta, Microsoft, and TikTok. For instance, Period Calendar transmits device IDs and device information to Google and InMobi without offering users any way to disable this. Stardust shares data with Facebook and AppsFlyer, though this feature can be turned off through phone settings. Despite these widespread issues, the only app recommended without reservations was Euki, which stores all data exclusively on the user's device and does not require account creation.
“Users deserve better—and at the very least, they should understand what is actually happening with their data.” — Shoshana Wodinsky
The study also highlights the serious consequences that can arise from using such apps. Sarah Hegeman noted: “The mere act of using a reproductive health app can already have consequences—for example, tipping off law enforcement about where to find a valuable trove of health data.”
According to the research, Flo and Clue do not transmit health data to third parties. They only inform advertising partners that the app is being used, a feature that can be disabled. However, these apps collect more health data than others and store it on their own servers. Flo, in particular, settled a case with the U.S. Federal Trade Commission in 2021 over sharing data with Meta, Google, and others.
In summary, Mozilla's research reveals serious data privacy issues in many popular menstrual cycle tracking apps. In a world where personal data surveillance is becoming the norm, it is crucial for users to be aware of the risks associated with using such technology.
Mozilla's study underscores the importance of user awareness regarding how personal data is handled by menstrual cycle tracking apps, especially in light of shifting reproductive rights laws in the United States. This can have severe implications for women, as information about their reproductive health may be used not only for advertising but also in law enforcement contexts. With growing attention on data privacy, users should carefully choose the apps they use and review their privacy policies.
As concerns about data privacy intensify, particularly in sensitive areas like reproductive health, it's crucial to stay informed about how tech giants handle user information. In a related context, Meta is facing pressure to enhance protections against intimate deepfakes, highlighting the ongoing challenges users encounter in safeguarding their personal data online.