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News
Menstrual cycle tracking and "cycle syncing" are booming in popularity, but a new BMJ analysis warns the practice may do more harm than good. Apps often misidentify cycle phases, health recommendations lack solid evidence, and some advice — like ditching hormonal birth control — can raise pregnancy risk. Experts say clinicians need to step up as trusted sources of evidence-based menstrual health education.
Cycle syncing is trending — but experts say the science isn't keeping up
"Cycle syncing" — adjusting exercise, diet, and daily habits to align with menstrual cycle phases — has gone mainstream, fueled by apps, influencers, and wellness programs. But a new analysis in The BMJ is pumping the brakes. Researchers warn that the technology behind menstrual tracking is often unreliable, the health recommendations it generates are poorly supported by evidence, and some advice may actively harm users.
A key concern: many apps estimate cycle phases simply by counting forward from the first day of bleeding, ignoring the fact that ovulation timing varies widely and cycles without ovulation are common. Even wearables like the Oura Ring, which use temperature and pulse data, leave clinicians struggling to interpret the results meaningfully.
Key Takeaways
Why it matters: With an estimated 50 million people using period tracking apps globally, the stakes are high. Experts urge clinicians to proactively offer evidence-based menstrual health education before patients turn to less reliable sources.
