Who sees your cycle data? What a 2021 FTC order teaches builders about sensitive health data

Cycle-tracking apps now use AI to predict periods and fertile windows. Many people find that useful, and I'm not here to tell anyone to delete theirs. But the data is some of the most sensitive a person creates: it can show whether someone is trying to conceive, pregnant, or unwell.

One case

In 2021 the US Federal Trade Commission finalised an order against Flo Health. The FTC alleged that the app told users their health data would stay private while sharing it with analytics and marketing providers, including those of Facebook and Google. Flo has said the settlement was not an admission of wrongdoing. The order requires affirmative consent before sharing health information and an independent privacy review. Sources: the FTC press release and news coverage.

That is one case from a few years ago. I'm not saying every app does this, and I have not audited any app.

The questions, for users and builders

1. Who sees my data? As a builder, write the list of every system that touches it, including analytics and error tracking.
2. Why? If you cannot say why a recipient needs it, it should not get it.
3. For how long, and can I delete it? Retention is a feature, not a footnote.

How I answered them in Tabibu

When someone uploads a document, the file is not stored. The answer is kept for about 48 hours, and there is an opt-in "Keep for 30 days". Those are design choices I can state in a sentence, which is the test I use. They are not a security audit, and I would not call them one.

The lesson

For builders: sensitive health data needs a clear answer to "who sees this, why, and for how long?" before launch, not after a complaint. For users: ask the same three questions of any app you give it to.

Do you know who your cycle app shares data with?

I post short videos in this series on LinkedIn and TikTok; come say hi.

General information, not medical advice.