What does your cycle say about you?

Menstrual data is finally being recognised for its value in medical science, but are period tracking apps putting our privacy at risk? Femtech World editor Sarah Sinclair reports.

Period‑tracking apps don’t just collect data on our cycle. Under the banner of “personalised health insights”, they log information such as sexual activity, contraception use, exercise, moods, and sometimes even our location. This can reveal intimate insights about an individual or group, from their political preferences and social habits to sexual and gender identity, mental health problems, and reproductive choices. 

The risks associated with this, should this data fall into the wrong hands, are highlighted in a recent report from researchers at the University of Cambridge. They include intimate partner violence, risks to job prospects, workplace monitoring, and health insurance discrimination.

According to the report’s lead author, Dr Stefanie Felsberger, apps that track menstrual cycle data are a “goldmine” for consumer profiling, the financial value of which is “vastly underestimated” by those who now rely on them as a part of daily life.

Last week, Flo Health, one of the world’s leading cycle tracking apps, settled a data privacy case in the US. The company was accused of unlawfully sharing users’ data with the social media platform Meta – claims which both Flo and Meta have denied. A settlement was reached, with no admission of wrongdoing, after the judge presiding over the case highlighted an “insurmountable” lack of evidence on behalf of the claimants. 

Flo Health has always refuted claims that it has shared users’ data with third parties. Even so, the case raises legitimate questions around how much we really know about where information about such intimate details of our lives could end up.

An analysis of 29 menstrual apps by researchers in Australia last year found that existing privacy laws were not adequately protecting users and their intimate information. While consumers are protected by GDPR laws in the UK and EU, police were recently issued guidance on how to check women’s menstrual tracking apps and medical records after sudden pregnancy loss.

In the US, following the fall of Roe v Wade, more restrictive abortion laws and less consumer protections could lead to reproductive data being weaponised against women in the form of private lawsuits, and insurer profiling, with location pings and private messages already being used in cases prosecuting women for illegal abortions. 

Global downloads for the three most popular apps were estimated to exceed 250 million last year. The fact that so many women and non-binary people now rely on this technology is indicative of a desire to have more control and agency over our health, whether that’s for general wellbeing, or the management of menstrual-related symptoms and long-term health conditions. 

Women are significantly underserved by existing healthcare systems, particularly when it comes to reproductive health. Many people use these apps in an attempt to plug the gaps left by the public health system, as a report by the Women and Equalities Committee (WEC) highlighted in the UK last year. They allow users to access vital information about their hormones, cycle characteristics and symptoms, which have been overlooked – potentially for years – by healthcare professionals. 

Menstrual cycle data is not only valuable from a financial perspective. More importantly, it is crucial for advancing research and improving health outcomes. As well as flagging concerns such as pain and heavy bleeding, it can also indicate signs of medical conditions, such as diabetes, thyroid disorders, polycystic ovarian syndrome, rheumatoid arthritis and irritable bowel syndrome, research shows. Scientists at femtech startups like Qvin are harnessing menstrual blood as a potential diagnostic tool for conditions such as endometriosis and for the early detection of cervical cancer. 

The fact that this data is not routinely collected by clinicians is not a careless oversight, but yet another symptom of a modern medical system in which women – and their bodies – have been entirely overlooked. Experts writing in the Lancet Obstetrics, Gynaecology, & Women’s Health, last month, said this data was an ‘underused but powerful tool’ for understanding women’s health, which should be routinely collected along with other measures such as BMI, blood pressure and cholesterol.

Separately, University of Cambridge researchers have urged public health bodies, including the NHS, to build their own state-governed menstrual tracking apps. 

These privacy-first platforms could collect valuable insights from menstrual cycle data, while ensuring users’ privacy with on-device storage and strict consent mechanisms. With transparent opt-in processes, anonymised data collected through public tools could also be used to advance much-needed research into women’s health. 

Following the publication of the NHS 10-Year-Plan and its promise of a shift from analogue to digital, there is potential for innovation in public health, with the mention of public-private partnerships to help deliver the tools that could make a real difference to women’s health outcomes. Perhaps the digital health record Wes Streeting has promised could also integrate data collected on a patient’s menstrual cycle. 

However, for now, it remains unclear exactly how and when this digital transformation will be delivered, and as with any structural overhaul in the public sector, it’s unlikely to be anytime soon.  

In the meantime, private innovators can lead by example with products that offer transparency, minimal data collection and medical validity. And consumers can support meaningful innovation by choosing apps with encrypted, on-device data storage.

Tech can be a force for good when it’s done with the right intention. In her latest impact venture, Amber Vodegal, the founder of the global Pregnancy Plus+ (which she sold to Phillips in 2017), is now developing a period-tracking platform that is privacy-safe and free at the point of use. 

Instead of storing data on external cloud servers, 28X will use on-device, fine-tuned open-source GenAI models with suitable guardrails to avoid sharing with third parties. Vodegal also plans to make the technology open-source to allow other developers to use and build on it.

Now that the medical and scientific value of menstrual data is finally being acknowledged, it deserves to be taken seriously by both private and public healthcare providers. This data can reveal intimate details about our lives, from our reproductive health to who we are as people. Treating it as a commodity – without our consent – is not only unethical, but undermines genuine efforts to address the gender health gap.