Period-Tracking Apps Are Monetizing Women’s Extremely Personal Data

(Bloomberg Businessweek) -- Sarah Martin, a Berlin-based aid worker who specializes in women’s issues, used to track her periods in the same paper planner where she wrote down her work appointments. Sometimes she’d also draw a little heart for the days she’d had sex. Nowadays she uses a smartphone app to track her cycle, because “the app feels more private and discreet,” she says, even though she realizes it’s probably not.

Martin is one of more than 100 million women around the world who each month use free menstruation-tracking apps with such names as Flo, Glow, Ovia, and Clue, and may want to be warier about that. Some women use these apps to help them get pregnant or avoid pregnancy; others simply to get a better handle on what their bodies are doing. In any case, the apps have built in a wide variety of other health-tracking features, too, and most are widening their use of the data they collect to make money, betting they’ll be able to build business models off this extremely sensitive data.

Apps don’t have to meet the privacy standards of, say, doctors or hospitals. They also aren’t always right. See Natural Cycles, a U.S. Food and Drug Administration-approved app that drew criticism last year after women in Sweden reported unwanted pregnancies while using it. Swedish health regulators asked the company to more clearly disclaim that it doesn’t promise 100 percent accuracy.

“No two cycles are exactly the same, even in the same woman,” warns Anna Glasier, a leading contraception researcher at the University of Edinburgh. An app “does nothing but rely on people not having intercourse at a certain point in the cycle. And we know that doesn’t work very well.” Natural Cycles said in a statement that it’s typically 93 percent effective, based on a study of about 22,000 women.

Some period-tracking apps ping you with requests for more data (when did you last have sex? did you use an ovulation test this month?) or suggest exercises (help keep your breasts young and perky!). Combined, the apps have raised at least $350 million over the past several years. Flo leads the U.S. market, with about 6 million of its 28 million monthly users located in the States.

Belarusian twins Yuri and Dmitry Gurski started the company in Minsk in 2015 and have refined the app to let women record their moods, sex drive, even pimples, as well as basal body temperature measurements that can help pinpoint ovulation. The company says it has collected more than 13 billion data points, and its team of 15 data scientists sift the data for patterns. Based partly on their conclusions, the app monitors irregular periods and sends an alert when a user is likely to conceive. “A lot of people have thanked me after the app helped their family get pregnant,” Yuri Gurski says.

The brothers’ background wasn’t exactly in women’s health: They made their name selling Google and Facebook Inc. a pair of viral photo apps, one of which morphed users’ faces into those of Stalin or Leonardo DiCaprio. Yet by last summer they were selling targeted ads to Procter & Gamble Co. and Bayer AG. A quiz backed by Bayer, which sells a type of intrauterine device that can regulate heavy period flow, prompts users to think about whether their menstrual bleeding is unusually heavy. “You can really bring the right content to the right place,” says Bayer physician Cecilia Caetano. A Flo-using teenager might get ads on tampon use, while a 30-year-old might be pitched ovulation tests.

Flo says it’s already profitable if you don’t account for marketing expenses and that a subscription model it rolled out in the fall shows promise. So far, about 3 percent of users have signed up to pay as much as $10 a month for extra articles and data.

Glow, backed by PayPal co-founder Max Levchin, began marketing in vitro fertilization directly to users about a year ago. Ovia is pitching a paid version of its app to insurers and large employers who want a heads-up on how many of their members or employees want to conceive. Both companies are certified compliant with U.S. patient privacy rules and say they don’t sell data to third parties.

Ida Tin, chief executive officer of Clue, Flo’s biggest Western rival, says she strongly opposes running targeted ads, which she deems invasive. Although Clue’s terms of service allow user data to be shared with academic researchers and don’t explicitly rule out commercial use, the company has promised not to go that route. “My dream is that people will read the terms of service,” says Tin. “I don’t have to optimize every little thing I do and sell my data left and right … that’s not why I’m doing this.”

Her app is heavy on analytics, letting women track health problems that may be linked to their periods—everything from constipation to depression—and charging about $1 a month for more data analysis, including a feature that predicts upcoming symptoms based on previous ones. Clue wouldn’t say how many of its more than 10 million users have subscribed. Tin says the investors who’ve supplied $30 million in capital are patient.

So far, Clue appears to be the exception. Barring some form of regulation, the market is likely to keep sliding toward ever-more-intensive data mining. In China, women seem fine with that, says Chai Ke, CEO of Dayima (slang for “menstruation”) in Beijing. His service crunches deeply personal information with permission from users. “If you know where I’m living, and I’m pregnant, and which hospital I’m giving birth in, and your salesman approaches me as I’m coming home from the hospital,” he says, “then that’s a problem.”

To contact the editor responsible for this story: Jeff Muskus at, Rick SchineMarthe Fourcade

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