Oura has announced the addition of Fertile Window to its Cycle Insights feature, expanding its women’s health tracking capabilities. The new feature, currently rolling out to iOS users with Android following in coming weeks, uses physiological data to estimate users’ most fertile days.
The feature leverages Oura’s existing temperature tracking capabilities, along with other biomarkers including heart rate, heart rate variability, and respiratory rate to predict and detect fertile days. This development builds on Oura’s established presence in reproductive health tracking, including their partnership with Natural Cycles, the FDA-cleared birth control app.
“Understanding your fertile window is key to improving your body literacy, cycle awareness, and your overall reproductive health,” notes Dr. Neta Gotlieb, Women’s Health Senior Product Manager at Oura. “One of the things I repeatedly hear from fertility clinicians is how stressful it is for their patients to actively track their fertile window. We created the Fertile Window feature to help minimize this stress with passive tracking and empower women through self-knowledge.”
The launch is particularly significant given Oura’s existing capabilities in temperature measurement. The ring’s sensors generate 1,440 data points daily and can measure temperature changes as precisely as 0.13°C (0.23°F). This accuracy has already been validated through their Natural Cycles partnership, where the ring’s temperature data is used for fertility tracking and natural birth control.
Importantly, Oura emphasizes that the new Fertile Window feature is designed for conception support and body literacy, not contraception. For birth control purposes, users are directed to Natural Cycles, which maintains a separate FDA clearance for this use case.
The development reflects a growing trend in femtech toward passive monitoring solutions that reduce the user burden of active tracking. While traditional fertility tracking often requires manual temperature taking and data entry, wearable devices like the Oura Ring can collect this data automatically during sleep.
The company notes that the feature accounts for natural cycle variations, acknowledging that the traditional assumption of day-14 ovulation and 28-day cycles is oversimplified. According to anonymized Oura member data, cycles can vary from 20-40 days, with individual variations of up to 8 days.
