Period apps: tracking you or your period?

You might think that monthly periods are a normal, expected part of period-havers’ lives. You would probably be wrong; I hear every so often about that first day of period or premenstrual symptoms catching folks by surprise. It’s like, 20 or so days pass and all of a sudden you completely forgot what it felt like to be moody, crampy, and bleeding. Luckily, there’s an extremely convenient solution to this problem: period tracking apps.

Apps like Clue, Flo, and more allow you to input your bleeding days and do all the hard math for you. They’ll notify you when they think you’re about to start bleeding, PMSing, or ovulating. They’ll compile all of your historical periods to give you personalized cycle predictions. For those looking to get pregnant, this can be incredibly helpful because our bodies don’t typically notify us of our daily fertility in any significant way. If you’re detail-oriented, you can even track specific symptoms and activities. Depending on the app, this can range from what types of period products you used on a given day, your sexual activity, your level of social interactions, the texture of your skin and hair, or your basal temperature. If you can name it, you can log it.

And if you can log it, someone can store it in a database. Given the extremely personal nature of all of this information, this fact might — and should — be of note to period app users. These days, data privacy is a hot topic. Companies like Google and Facebook are notorious for buying user data to tailor ad experiences. Period tracking apps are selling. In 2019, it was found that the makers of the period app Flo had been selling user data to Facebook for three years.

There are a lot of complexities surrounding data brokerage, and I could spend a lot of time enumerating them all, but the bottom line is this: if you’re not paying for your period tracking service, someone is, and it’s likely by buying your data. If you don’t want another person to know that you had a zit on your nose on Tuesday and then took ibuprofen for your moderate-severe cramps on Friday, you should probably be very cautious about which period apps you use, if any, and how you use them. If you’re looking to keep yourself protected, School of Computer Science professor and data privacy expert Jason Hong suggests: “Apps that use Apple's HealthKit have stronger protections in place. The data is encrypted and stored locally, meaning that Apple can't decode the data.”

This is especially relevant now, as women’s reproductive systems are under more regulation and scrutiny than ever. After Roe v. Wade was overturned in June 2022, many became concerned that the data garnered from period apps might be used against them in the name of upholding new abortion bans in some states. Data collected about unprotected sex, gaps in birth control, the use of Plan B, and irregular bleeding or cycle length could all be strong indicators that someone has had or will try to obtain an abortion. Jason Hong says, “There is tremendous potential for false positives of ([people who] seemed to have a pregnancy end early, perhaps due to miscarriage or an abortion or premature birth) … There will likely be some overzealous prosecutors. There is also the bounty program in Texas where people can turn in other people [who get abortions]. And there will also be pushback from some tech companies, but how much is unclear.” As a result of so much ambiguity, most advised switching to paper and erasing any trace of your online menstrual presence last summer. One proposed solution is to inundate apps with false data from our non-menstruating allies. Hong says this would “[blunt] the utility of the data if there is a dragnet that trawls the data for possible abortions. I think this is not a bad idea, but only works if there are lots of men that do this, and if they fill out the data in a manner that looks realistic.”

There are no laws in place to stop prosecutors from making use of data tracked on period apps. There are few laws in place to stop prosecutors from making use of any kind of data. That is, even if your period tracker isn’t giving away that you’ve done something illegal in your state, companies that buy data from your period tracker might. This is true for almost any data though — it is well known that location data, text messages, and other digital use data can be used in court cases. It is for this reason that some advise against deleting your period app in panic; getting rid of it probably won’t protect you when it comes to abortion.

In some cases, too, data collection by period trackers is completely benign. Clue, for example, operates under UN law which prohibits the sale of data. Instead, Clue collects anonymized data solely for research purposes, and heavily vets each research team that applies to use their database. Apple has paired with Harvard in a similar data transfer research initiative. In each case, the goal is always to learn more about the menstrual cycle and educate others. As someone who thinks we have barely scratched the surface on the topic of menstrual health, I have a hard time arguing that data collection for research is unfounded. So I won’t argue that. Instead, I’ll say that I hope those who are continuing to use period apps are well-informed about the risks and becoming better-informed about themselves by tracking their symptoms. And I hope we never enter an era where people who menstruate have to write their cycles down on paper out of fear.