How to Keep Your Apple Watch Ovulation Data Private

    In a post-Roe world, period tracking might expose people to risks. But safeguarding your reproductive privacy in other ways may be more important.

    Apple Ovulation tracker seen on the iPhone and Apple Watch. Photo: Apple

    “Understand your cycle like never before.” That’s how Apple is promoting the temperature-sensing capability that’s built into the new Apple Watch Series 8. The temperature data, collected while you sleep, provides an added dimension to Apple Health’s pre-existing period tracking feature, and is meant to provide retrospective ovulation estimates and improve period prediction.

    The new feature comes just months after the Supreme Court’s Dobbs v. Jackson Women’s Health Organization decision ended the constitutional right to abortion. That decision raised fears that law enforcement in states where abortion is now illegal could use data from period tracking apps to help prove a person had an abortion. 

    Earlier this year, Consumer Reports evaluated the privacy protections offered by several period tracking apps. With Apple now aiming to improve the accuracy of its cycle tracking, should Apple Watch users be concerned about the security and privacy of the data collected by this (optional) feature? 

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    While the three standalone apps we recommended in our evaluation (drip, Euki, and Periodical) provide solid privacy protections, experts say Apple Health’s privacy protections are stronger than those of many of the most popular and highly downloaded period tracking apps available. 

    More importantly, many advocates have pointed out that period tracking data is not likely to be the most useful evidence law enforcement could use to prove someone had an abortion. To keep your reproductive health information secure, measures like encrypting your messaging and enabling disappearing messaging, keeping your search and browsing history private, and protecting yourself from location tracking should be higher priorities, experts say.

    Here’s what you need to know about the privacy of Apple Health’s cycle tracking, how to ensure your data stays as safe as possible if you do choose to use Apple Health, and what you need to know about the most important steps to take to protect your reproductive health information.

    Apple Health and Privacy

    Consumer Reports didn’t compare Apple Health to the other period tracking apps in our evaluation. That’s because unlike a discrete app, Apple Health is integrated into the larger Apple ecosystem in a way that makes it challenging to account for all the possible ways someone might use it, says Bill Fitzgerald, a privacy researcher in CR’s Digital Lab who conducted our analysis of period tracking apps. We can’t isolate Apple Health’s period tracking to directly compare it with individual third-party apps, for which we can perform a more focused analysis. 

    That said, Apple Health on its own has several advantages over many third-party apps. The major one is encryption, says Jon Callas, director of public interest technology for the Electronic Frontier Foundation (EFF).

    When your devices are locked and protected with a passcode (or Touch ID or Face ID), Apple says that Health data, including Cycle Tracking data, is encrypted. And, when you opt to store Apple Health data in iCloud’s backup system, it’s encrypted on your device, in transit to Apple’s servers, and in storage. That means the company can’t read your data, only your own devices can, says Callas, who formerly worked at Apple as a security reviewer.

    Such encryption also means your data is better protected against security risks associated with third-party sharing. You can optionally choose to share Apple Health data with a healthcare provider, however, which means you’ll have to trust the data privacy practices of that provider (though healthcare providers are some of the few entities bound by HIPAA). 

    Overall, Apple Health isn’t a bad choice for cycle tracking when it comes to keeping your reproductive data private, says Yael Grauer, program manager of CR’s Security Planner

    Still, CR’s Fitzgerald recommends that consumers err on the side of caution and opt for one of the period tracking apps we were able to evaluate thoroughly and that we found to minimize privacy risks.

    “In our tests, we can have visibility into how these services work,” Fitzgerald says. “Some of these apps have open source code, and they are built for a very clearly defined purpose—not as part of a billion-dollar product system—and with a deep understanding of what people tracking their cycles need. That matters.”

    Tips for Using Ovulation Tracking on Apple Watch

    If you do want to use the ovulation tracking feature on your Apple Watch, you need to have “Track Sleep” enabled along with “Cycle Tracking.” You can also turn off this feature by disabling “Wrist Temperature” in the privacy settings in the Watch app on your iPhone.

    Apple notes that the Watch isn’t a medical device and shouldn’t be used to prevent pregnancy, and that ovulation tracking provides only an estimate of when ovulation occurred, not a guarantee. CR has not tested the accuracy of this function, though an Apple spokesperson told us it validated the results against standard ovulation predictor kits in a study of 266 people.

    To ensure you get the benefit of encryption for your backed-up, tracked period data, you need to be using iOS 12 or later and have 2-factor authentication enabled, according to Apple. Your Watch also needs to be secured with a password, Apple says, to keep the data stored on the Watch itself encrypted.

    Since you can also grant third-party apps permission to access Apple Health, it’s wise to check regularly to make sure you haven’t inadvertently enabled sharing you don’t actually want. In your Apple Health profile, under Privacy, tap “Apps” to check and change what data is shared with compatible apps on your devices. You may want to set up a reminder for yourself to check these permissions regularly.

    Concerns About Period Tracking Data

    An important question for consumers is not just whether the Apple Watch’s new ovulation tracking feature specifically should be of concern, but to what extent period tracking in general puts people at risk. Experts we spoke with pointed out that period tracking data on its own isn’t necessarily the most important type of data to protect in a post-Roe world.

    Maggie Delano, PhD, an assistant professor of engineering at Swarthmore College who has written about data privacy post-Roe, says that so far at least, it seems like law enforcement has not been doing sweeps of period tracking data to find potential abortion recipients. There are less circumstantial and more concrete forms of evidence that are easier for law enforcement to access, Delano points out, like unencrypted text messages to a friend or a history of searching the internet for abortion pills.

    For more detailed tips from CR and other experts on important ways to protect your health data, see the best practices detailed in CR’s "These Period Tracker Apps Say They Put Privacy First. Here’s What We Found." and "How Private and Protected Is Virtual Reproductive Care?," along with this reproductive health privacy guide from the Digital Defense Fund. And learn more about protecting your location data, which Callas says should also be a higher priority than protecting period tracking data.

    Still, CR’s experts say protecting oneself against these privacy intrusions shouldn’t all be the responsibility of consumers in the first place. “The fact that this is a conversation we need to have is a sign of how far the power balance has shifted away from consumers,” CR’s Fitzgerald says.  


    Catherine Roberts

    As a science journalist, my goal is to empower consumers to make informed decisions about health products, practices, and treatments. I aim to investigate what works, what doesn't, and what may be causing actual harm when it comes to people's health. As a civilian, my passions include science fiction, running, Queens, and my cat. Follow me on Twitter: @catharob