Gina Neff
Executive Director, Minderoo
Menstrual cycle tracking apps (CTAs) are popular digital tools that people turn to for health information.
The three most popular of these apps were downloaded more than 200 million times in 2024.
The market for femtech is projected to exceed $60 billion by 2027, with CTAs accounting for half of that.
Accessing relevant reproductive health care – let alone a diagnosis for illnesses related to the menstrual cycle – is fraught.
It takes women an average of eight years to get an endometriosis diagnosis, for example.
CTAs provide users with a centralised place to track menstrual cycles, predict periods and fertility and access menstrual health information, and this data could help them have different kinds of conversations with their care providers.
Mapping the Problem
The problem is that CTAs gather data that falls into a regulatory gap.
CTAs collect some of the most intimate health information about people: Cycle information, family planning decisions, broken condoms and other sexual activities, emotional wellbeing, medicine intake, and pregnancy experiences.
Yet, users’ reproductive health information is often not afforded the same protections as conventional medical information, making menstrual cycle data ripe for extraction and commodification.
CTAs turn personal health information into data points to be collected, analysed and sold.
This poses risks and harms for users and society, as menstrual cycle tracking data can be – and has been – used to control people’s reproductive lives.
In a new report, published by the Minderoo Centre for Technology and Democracy at the University of Cambridge, we examine the risks women face when cycle tracking apps lack proper governance.
In the UK, menstrual cycle tracking data falls into special category data, which requires explicit consent and more safeguarding.
The implementation of these protections for data from CTAs is notoriously lacking. Many app companies directly shared intimate health information with Facebook and other advertisers.
In 2018 and 2019, Privacy International found that 61 per cent of 36 apps tested automatically transferred data to Facebook when users opened an app.
Their May 2025 follow-up investigation found that apps continue to share device data, which can be used to identify users, with a wide range of third parties and sometimes without explicit explanations in app privacy policies.
This data is exceedingly valuable. Menstrual data, in particular, overlaid with existing user profiling data sets, can reveal a lot about users: Physical illnesses, sexual and gender identities, social habits and consumer choices, mental health conditions, and reproductive choices, such as intention to conceive.
This data is also powerful. Menstrual cycle tracking data can also include information about miscarriages or a user’s access to abortion pills or services.
Imperfect tracking habits or disorderly cycles might also be misconstrued as access to abortions. Menstrual tracking data is used to police people’s reproductive lives.
Police investigations into unexpected pregnancy loss in the UK have used CTA data.
Recent guidance from the National Police Chiefs’ Council advised that digital devices could be seized to help investigators “establish a woman’s knowledge and intention in relation to the pregnancy”.
The guidance suggested these could include Internet searches, messages to friends and family, and menstrual cycle and fertility trackers.
Better Menstrual Tracking Technologies and Menstrual Care
Women deserve better. Even when users are concerned about their data, most people underestimate its commercial value and potential risks.
The apps add value to women’s lives, and so women are unlikely to stop using them. Policymakers can help make these apps – that women reach for to manage their health and understand their bodies – safer and better.
The companies that make these apps must also do more to earn users’ trust.
In our report, The High Stakes of Tracking Menstruation, we outline a path forward.
First, we argue that improved care for menstrual and reproductive health is imperative: This means research collaborations on menstrual health and education initiatives.
We identify menstrual data stewardships as a possible pathway and propose including digital literacy and menstrual technologies as part of the national curriculum on menstrual health.
Second, we need better enforcement of existing regulations to protect women’s menstrual health data. App developers need incentives to improve data governance and security, and to work towards providing users with ways to safeguard their data in legal contexts where their tracking data might be misused.
Last, public health bodies and researchers should develop new governance models for cycle tracking apps, with a safety-by-design approach. This could include an NHS-designed app or researchers using CTA data to improve women’s health. These steps could help to engender trust in the process.
Final Thought
What drives the popularity of period tracking apps is people lacking access to relevant information on how to live with menstrual cycles, and access to better menstrual health care.
CTAs represent an individual solution to a much larger gap in health care.
Meaningful change requires systemic solutions – like comprehensive menstrual health education and strong regulatory measures – and giving reproductive care the same value as conventional healthcare.
Femtech has helped to sell a vision of the future that empowers people through digital data.
But without fixing the problems and risks that today’s femtech tools and data present, that vision will be one that is heavy on selling and light on empowerment for health.
Featured image via ViDI Studio / Shutterstock.
