Nearly a third of women in the United States use a period-tracking app at some point in their lives, according to a survey from the Kaiser Family Foundation. Tens of thousands are now scrambling to delete them over privacy concerns in the wake of the Supreme Court's decision to overturn Roe v. Wade.

Apps that help monitor menstruation and fertility often contain heaps of personal data. Flo, Clue and Glow, among many others, help women know when to expect their periods, track fertility, manage birth control use – and potentially help with zeroing in on a myriad of other health-related concerns.

Every woman I know uses one, from teens trying to figure it all out to women starting menopause. So, what’s the risk?

Period-tracking apps and privacy concerns:  We answer your questions

Are period trackers risky?

You may have seen the trending hashtags and advice to “delete your #periodtracker” pop up all over your social feeds lately. Privacy advocates say the biggest concern right now is that the sensitive data these apps collect could potentially be used against people in states where abortion may be criminalized.

But companies have been sharing and selling our personal data for years without warning us. Still, period-tracking apps obviously know a lot about people who use them – but how much information is accessible by the companies behind them – or by outside sources? More than you might think.

The makers of one of the top apps in this space, Flo Health Inc., settled with the Federal Trade Commission in 2021 over claims it shared sensitive health information with outside advertisers and analytics companies without proper disclosure.

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In 2020, another highly regarded app called Glow, which focusses on fertility, settled a suit with the state of California over “serious privacy and basic security failures that put women’s highly-sensitive personal and medical information at risk.”