Digital menstrual tracking risks creating more harm than benefit and requires greater scrutiny, warn experts in The BMJ today.
Widely promoted to women and girls on social media and by tech firms, menstrual tracking apps and other "femtech" tools claim to scientifically analyse personal data to improve health, wellbeing, and performance based on a user's menstrual cycle.
But Katharine Lee and colleagues argue that neither menstrual tracking nor "cycle syncing" - adjusting diet and exercise according to menstrual cycle phases - have been convincingly shown to improve health or other performance measures.
And they say the slick marketing of digital menstrual cycle tracking apps and the scientifically suspect practice of cycle syncing "require critical interrogation and resistance."
For example, decades of sports science research shows no overall effect of menstrual cycle phase on performance, injury risk, or health, and any effects found have been trivial and highly individualised. Research on phased based dietary interventions to reduce menstrual cycle symptoms or improve performance is also generally inconclusive, highly individualised, or speculative.
Even if menstrual phase corresponded with fluctuations in health, performance, or vulnerability to injury in individuals, simple digital tracking technologies cannot reliably predict such variation, they explain.
Aside from their weak evidence base, digital cycle tracking technologies also come with serious risks, they write, including wasted time and labour, unwanted surveillance, risks to health data privacy, and may distract from or even threaten efforts to advance women's health.
"These apps have the potential for widespread impact on the wellbeing of women and girls. Yet, the evidence that these digital tools can actually help in the management of menstrual conditions, boost health, and provide insights into exercise and nutritional needs is lacking," they warn.
Suggestions to address the risks of digital tracking include strengthening protections for consumer and employee data, improving user awareness of how data are used, and advising clinicians to recommend apps to patients only when they meet stringent standards.
Others have emphasised the need to regulate misleading marketing and resist the commercial co-option of feminist activist rhetoric.
Tailoring health communications approaches to the social media environments where users encounter cycle syncing content may offer an opportunity to build the public's trust in more credible sources and counteract misleading narratives about hormones and health, they note.
Meanwhile, health practitioners, regulators, and the general public must be aware of and work to address the risks of these consumer technologies on women's health, they conclude.
