Period Apps Turned Your Cycle Into Ad Data. A Jury Said That’s Illegal.

Your period tracker knows when you’re trying to get pregnant. It knows your mood patterns, when you last had sex, whether you’re using birth control. For millions of users, these apps feel like digital diaries—intimate spaces to understand patterns in their own bodies.

That intimacy was an illusion.

On August 1, 2025, a California federal jury found that Meta had violated state privacy laws by collecting sensitive reproductive health data from users of the Flo period tracking app. The verdict sent a clear message: collecting intimate health data without proper consent isn’t just unethical—it’s illegal.

The Hidden Data Pipeline

Between 2016 and 2019, Flo promised users their sensitive health information would stay private. But behind the scenes, the app was sharing cycle dates, pregnancy goals, and sexual activity data with Meta through embedded tracking tools. Every survey question users answered was being funneled to one of the world’s largest advertising companies.

The data wasn’t just collected—it was processed for targeted advertising, turning the most intimate details of reproductive health into marketing intelligence.

Why This Matters More Than Ever

This privacy violation takes on new urgency in a post-Roe legal environment. In states with restrictive abortion laws, menstrual tracking information could theoretically be subpoenaed in legal proceedings. While no major cases have emerged yet using period data as evidence, the legal framework has fundamentally shifted.

Data that was once simply personal now exists in a world where digital health records could become legal liabilities. A late period logged in an app could theoretically be scrutinized by law enforcement in certain states.

The Technical Reality

The Flo case reveals how data collection really works in most health apps. Software development kits (SDKs) embedded in apps can transmit user interactions to third parties in real-time. Users see a simple interface asking about their cycle, but each tap and selection can trigger data transmission to advertising networks.

Most period tracking apps today still operate this way. They’re free because users aren’t the customers—they’re the product.

What True Privacy Looks Like

The solution isn’t better privacy policies or clearer consent forms. It’s fundamentally different architecture. Apps designed for real privacy would:

Keep all sensitive data on your device by default, with no automatic cloud backup. Use end-to-end encryption for any data that needs to sync between devices. Collect only the minimum data necessary for the app to function. Have no embedded tracking tools, analytics SDKs, or advertising partnerships.

Most importantly, they’d be funded by users, not advertisers. When you pay for an app, you’re the customer. When an app is free, you’re often the product being sold.

Legal Protection Has Limits

The California verdict against Meta is encouraging, but legal remedies come after the damage is done. By the time a court rules that data collection was illegal, your personal information has already been processed, analyzed, and potentially stored by multiple companies.

Real protection comes from technical design that makes harmful data collection impossible, not just illegal. The goal should be building systems where there’s nothing sensitive to subpoena in the first place.

The Path Forward

The technology exists to build period tracking apps that genuinely respect privacy. Local data storage, minimal data collection, and user-funded business models can eliminate the conflicts of interest that led to the Flo situation.

What’s needed now is user demand for these alternatives. As long as people accept “free” apps that monetize their health data, companies will keep building them. But when users start choosing privacy-first options—even if they cost money—the market will respond.

Making Data Useless to Adversaries

The ultimate privacy protection isn’t just keeping data away from advertising companies. It’s designing systems where even if legal authorities demanded access to user data, there wouldn’t be anything useful to hand over.

This means local-only storage, anonymous usage patterns, and technical architecture that makes surveillance difficult or impossible. The best defense against future legal risks is making sure sensitive data never exists in a subpoena-able form.

Your reproductive health data is some of the most intimate information you have. It deserves tools built specifically to protect it, not exploit it. The Flo verdict is a reminder of what happens when we trust companies that see our bodies as business opportunities.

The question isn’t whether better privacy-focused period tracking apps will emerge—it’s how quickly they’ll arrive and whether users will choose them over convenient but compromised alternatives.

The Meta verdict affects all Flo users in the United States who entered menstrual or pregnancy information between November 2016 and February 2019. Damages have not yet been determined.