Smartphone apps that log menstrual cycles turn out to be a treasure trove for marketers, gathering details about everything from workouts and diets to medication, sexual habits, hormone levels, and birth control use.
That’s what a recent report from the University of Cambridge’s Minderoo Centre for Technology and Democracy reveals. It says users don’t realize how valuable their data really is when they share personal info with profit-driven companies in an industry that isn’t well regulated.
The authors warn that if cycle tracking app (CTA) data falls into the wrong hands, it could lead to problems like job discrimination, workplace spying, biased health insurance decisions, cyberstalking-and even restricted access to abortion services.
They’re pushing for stricter rules around the growing ‘femtech’ field to keep users safe when their information is sold widely. They want apps to offer clear choices about what data gets shared instead of forcing all-or-nothing deals and suggest public health groups create alternatives to commercial CTAs.
“Menstrual cycle tracking apps are presented as empowering women and addressing the gender health gap,” said Dr Stefanie Felsberger, lead author of the report from Cambridge’s Minderoo Centre. “Yet the business model behind their services rests on commercial use, selling user data and insights to third parties for profit.”
“There are real and frightening privacy and safety risks to women as a result of the commodification of the data collected by cycle tracking app companies.”
Since most period apps target women trying to conceive, just knowing how many times they’ve been downloaded is extremely valuable commercially. Researchers say no other life event-except maybe buying a home-changes buying habits this much.
In fact, pregnancy-related info is thought to be over two hundred times more valuable than basic demographic data like age or location when it comes to targeted ads. The report also points out that advertisers can tailor ads based on where women are in their cycle-for example, promoting beauty products during high-oestrogen phases.
The top three period apps alone had combined global downloads around 250 million in 2024. Femtech-which includes digital tools focused on women’s health-is expected to hit more than US$60 billion (£45 billion) by 2027; half of that comes from cycle trackers.
Given this huge demand for period monitoring tools, the report suggests that Britain’s National Health Service (NHS) should make its own transparent app as an alternative to private ones-with features letting users consent if their data can be used in medical research.
“The UK is ideally positioned to solve the question of access to menstrual data for researchers, as well as privacy and data commodification concerns, by developing an NHS app to track menstrual cycles,” said Felsberger, who notes Planned Parenthood already has such an app in the US but there isn’t one like it in Britain yet.
“Apps that are situated within public healthcare systems, and not driven primarily by profit, will mitigate privacy violations, provide much-needed data on reproductive health, and give people more agency over how their menstrual data is used.”
“The use of cycle tracking apps is at an all-time high,” said Prof Gina Neff, Executive Director of Cambridge’s Minderoo Centre. “Women deserve better than to have their menstrual tracking data treated as consumer data, but there is a different possible future.”
“Researchers could use this data to help answer questions about women’s health. Care providers could use this data for important information about their patients’ health. Women could get meaningful insights that they are searching for,” Neff said.
In both the UK and EU periods tracking info counts as ‘special category’ personal information-like genetic or ethnic info-and has stronger legal protections. But still in Britain some women have been charged because period-tracking apps were misused related to illegal abortion access.
Over in the US officials have tried collecting menstrual cycle info aiming at limiting abortion rights too. Even so CTAs are only classed under ‘general wellness’ rules there with no extra safeguards offered.
“Menstrual tracking data is being used to control people’s reproductive lives,” said Felsberger. “It should not be left in the hands of private companies.”
Dive into investigations by media outlets along with nonprofits shows these apps often share info with advertisers and brokers plus tech giants like Facebook and Google too.
The report references research from Privacy International earlier this year revealing while big CTA firms updated how they handle sharing user info recently device details still get collected without real consent across UK & US markets.
This means even after improvements user details get passed along third-party services such as cloud networks moving information around plus outside developers hired for certain features inside these apps.
A simple fix might be adding delete options inside these commercial apps so folks can wipe out saved records both locally on phones *and* company servers – which would protect against misuse ranging from legal trouble right through medical issues down the road.
“Menstrual tracking in the US should be classed as medical data,” said Felsberger. “In the UK and EU , where this data is already afforded special category status , more focus needs to be placed on enforcing existing regulation.”
The paper stresses educating people better about digital privacy linked with period trackers. Researchers argue schools need lessons covering medical-related apps & online safety so young folks aren’t tricked by false health claims.
The report ‘The High Stakes of Tracking Menstruation’ was written by Dr Stefanie Felsberger with an introduction by Professor Gina Neff , published through Minderoo Centre for Technology and Democracy (MCTD).
