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period apps, caladeners, and a uterus on a red and beige bleed week background
period apps turn your menstrual cycle into numbers. Image: Tina Tiller

InternetJuly 21, 2022

How period apps turn your body into data

period apps, caladeners, and a uterus on a red and beige bleed week background
period apps turn your menstrual cycle into numbers. Image: Tina Tiller

Tracking their menstrual cycles with an app is an ingrained, useful habit for millions around the world. But period apps are also a reminder of how intimate data about our bodies enters the domain of technology companies, says Shanti Mathias, reporting for IRL. 

All week we are examining our relationship with menstruation in Aotearoa. Read more Bleed Week content here.

Every day for the last seven years, Becky* has opened an app on her phone to log her symptoms. What mood is she in? Does she have a headache? If she has her period, how heavy is it? Her app of choice, Clue, registers this information, telling her when she might be ovulating and when her next period is due. 

Becky started tracking her period while living in Tibet and travelling a lot. “It was very difficult when you’re climbing a mountain or visiting a monastery in the middle of nowhere, and [your period] comes and you’re like, shit!” A friend recommended the app and “it saved my arse,”, she says. Over years of use, Clue has turned the rhythms of her body into numbers, coloured graphs and calendars telling her what is happening beneath her skin. 

Every month, millions of people join Becky in tracking their periods. The two leading apps, Flo and Clue, together have over 55 million users on Apple and Android, and there are dozens of others. Essentially, these apps all do the same thing: send reminders to log menstrual-cycle symptoms every day and use algorithms for calculating when your next period is due, if you might be fertile or if you might be pregnant.

At an individual level, the insights of period apps can be tremendously useful for understanding and communicating what is happening in your body. But like the hundreds of other digital technologies promising to optimise health, they’re still ultimately using the most intimate of data to turn a profit.

Period tracking apps are designed to be easily interpreted, with information about menstrual cycle length presented on tidy graphs. “I like the visualisation of the data,” says Jess*, another longtime app user. “It’s a good way to look back on what is happening with my cycle.” 

bryndyl hohmann-marriott stands in the sunshine smiling
Otago professor Bryndl Hohmann-Marriott has been researching period apps for years

The apps quantify and package individual experiences of menstruation in a way that is easy for others to see, says Bryndl Hohmann-Marriott, an associate professor of sociology at the University of Otago who has been studying period apps for the last five years. “People are hoping to understand themselves better based on data,” she says. “There’s an [idea] that technology can know us better than we know ourselves.” 

The nature of periods heightens this desire for understanding, Hohmann-Marriot says. The menstrual cycle is constant, but most of it is invisible: the silent accumulation of blood around the uterus, the release of an egg into the fallopian tubes, the flow of luteinizing and oestrogen hormones through blood. The period itself is the only part of the process that is external, but the graphs and statistics – how long is your cycle? What are the signs of ovulation? How does your period change your sleep? – make the invisible parts of the menstrual cycle visible. This information is particularly useful for communicating your cycle to others. 

“Personal data can be very helpful,” says Holly Thorpe, a professor at Waikato University’s school of health, who researches sport and gender, including period tracking for athletes. Thorpe says that athletes are very used to being tracked, with information about speed and strength and sleep – and periods – being used to calculate nutrition and design training programmes. For the athletes Thorpe works with, acknowledging menstruation as part of their body can help them excel. 

Holly thorpe, a smiling white woman, looks at the camera
Professor Holly Thorpe has studied how period apps are part of athletes training’, but how do athletes feel about this?

Period tracking apps can also help individuals seeking diagnosis of menstrual disorders, like polycystic ovary syndrome (PCOS) and endometriosis. “One thing that app users and medical professionals agreed on is that it is helpful to have a consistent record of cycle and symptoms,” Hohmann-Marriot says. Because the medical system is traditionally dismissive of menstrual pain, there can be an “appallingly” long wait for a diagnosis of disorders connected to period pain. 

All the app users I spoke to for this story had shown information from the apps to their doctors. “You get 15 minutes with a doctor and it’s hard to remember everything that’s been going on,” says Jess. “It’s useful to have a visualisation to back yourself up and help you remember,” she says, adding that she appreciated that the app gave her solid information on her irregular cycles. 

Period tracking also helped Julie*, who used an app to record pelvic pains, the cause of which was a mystery. “This information became critical when I finally spoke to a specialist and they put me forward for endometriosis surgery,” she says. “I still use the app to track my periods so that I know when to expect flare-ups.”

As period data continues to be used for accessing healthcare and improving sports performance, there is a downside, says Hohmann-Marriott. “Often doctors weren’t taking [patients] seriously if they didn’t have [period tracking] evidence,” she says. The period tracker prioritises quantification as a form of knowledge, treating symptoms with numbers attached as more valid than descriptions or experience without the proof of a graph on a phone. In making the invisible visible, period apps also imply that only certain kinds of self-knowledge are valid. 

The individual popularity of period apps is part of a broader neoliberal technology culture, Hohmann Marriot says. She notes that neoliberalism is the water “we all swim in” and period apps are neoliberal technologies that expect users to be neoliberal citizens who “monitor themselves and are responsible for keeping themselves healthy”. Keeping track of periods can help users look after their bodies, but it does so in a way that generates profit for others. It’s the same logic that helps explain widespread use of Fitbits and Apple Watches, Strava, Headspace, and many others: to care for your body, you need to make it legible to corporations with numbers, and purchase phones and other products to maintain that care. 

phone on a background of apps
Period apps are among the many other useful services on your phone that make money with your data

It’s not just self-monitoring, though: it’s also about what we expect technology to be able to achieve. “These apps are designed in westernised and scientised ways,” says researcher Thorpe. “There are different cultural ways to know your body, your menstruation.” But this wealth of other worldviews isn’t included in period tracking apps. Users are expected not just to be diligent, self-tracking citizens, ready to seek help if anything goes wrong with their bodies, but to also fit into western – often cisgender – ideas of who has periods in the first place. 

“Being non-binary and Māori, the app didn’t feel like it was for me at all,” says Whiro*, a user who tracked their periods for three years with app Flo before stopping. “It was very focused on pregnancy for cis women.” 

There’s an expectation that “there’s a technology answer for everything”, says Hohmann-Marriott. For instance, app Natural Cycles is an approved contraceptive in the US, Australia and Europe, but that doesn’t mean it’s always effective. Many Natural Cycles users have found themselves unexpectedly pregnant. In her research, Hohmann-Marriott has found that period apps “are very focused on people with normal cycles, they’re terrible for people with irregular cycles”. 

“Can the apps really give us the information we want about ourselves?” she asks. “In most cases, probably not.” An app might market itself as providing users with information about when they’re ovulating, which is vital information for those avoiding or seeking pregnancy. But the algorithmic prediction relies on users being able to accurately self-report the consistency of their cervical fluid, which isn’t straightforward. Apps may also use entered data to suggest that you have a menstrual disorder. “Nobody checks if it’s accurate,” Hohmann-Marriott says. 

If accuracy isn’t the goal, what is? “I wonder about this a lot,” says Hohmann-Marriott. “It’s very straightforward to make a period app with a basic predictive algorithm… None of these are developed with doctors or health consultants, they’re added later.” The goal is not better health outcomes for users, although apps may market themselves as such, and many users find their trackers do help their health. But for the developers of period apps, the goal is profit. 

a woman's face overwhelmed by apps
Photo: Getty Images

Apps are also monetised with advertising. Some apps also charge users a premium for access to better insights about their periods; Flo, the most popular period tracking app, is notorious for this. “It gave me articles about my cycle, but they were behind a paywall, so I would never read them,” says Whiro. “It seemed like it wasn’t very genuine – but I didn’t buy a subscription, so I don’t know.” 

But the heart of the period app business model is the sale of user data. Last year, Flo settled a massive court case that alleged it had informed Facebook of user activity in the app, such as indicating an intention to get pregnant. While many period apps say they protect user data, there are dozens of apps, and many user agreements have “loopholes big enough to drive a truck through”, Hohmann-Marriot says. “It’s so easy to get an app out there – the proliferation makes it easy for the bad ones to hide.” 

With the Dobbs ruling in the US meaning that people who get abortions can be prosecuted, some have recommended that period tracking apps should be deleted. Apps, eager not to lose users, have responded by creating “anonymous” modes. Users I spoke to were aware of the risks of generating this data, but found it difficult to imagine the consequences. 

“What are they going to do with it, really?” asked Jess. “I guess they could sell it to Facebook.” 

This is an attitude Hohmann-Marriot has seen often in her research. “People have so little control over what that data is used for, [even] if you read the user agreements,” she says. “It’s hard to think about, more than any individual can imagine.” Beyond the individual repercussions of for-profit corporations holding onto information about your body which you’ve diligently quantified for them, there’s the bleak reality that omnipresent technology asks everything to be profit. It’s not just your period tracker, after all: other health apps know how much exercise people get; social media apps draw links between friends and social groups; entertainment services gather information on what people are interested in seeing and learning; map and ride-share apps turn information about the location of your body onto a coordinate in a server.

Once you enter information about your body into your phone, where does it go? (Image: The Spinoff)

Whether you’re a user paying to get past a paywall to see information about your period, a tracking app company selling information to others, or data brokers compiling information from a range of digital companies to advertisers who want to target you so that they can make money, this is a technology system that has profit baked in at every level. The belief that everything is profit, including everything you know about your body, is a relatively recent phenomenon, and it’s hard to predict the long-term implications of living in a society that exchanges useful services for information about everyone. 

But while the big picture of monetised data is important, app users are glad that period tracking is helpful to them. As Becky has recovered from a chronic illness over the past year, keeping track of her periods has felt empowering. “We don’t know a lot of things about our own bodies,” says Becky. “Having a period app or a Fitbit takes [your] health into your own hands, saying ‘this is my body, I know my body’.” She’s fully aware that there’s a cost to the insights period tracking has given her, and she’s willing to live with the trade-off. “We live in a world where so much data is collected in so many ways,” she says. “I think the benefit outweighs the risk for me.”

As users like Becky continue to make use of period apps in an environment where individuals expect to sacrifice their collective privacy for useful technologies, Hohmann-Marriott will at least have “limitless” angles to research. After all, smartphones and the data questions that accompany them are here to stay – and so are periods.

*indicates that the interviewee wanted their last name withheld, or asked to use a pseudonym

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