A new study published in the Journal of Medical Internet Research has validated Oura Ring’s ovulation detection capabilities, showing particular promise for people with irregular cycles who are often underserved by traditional tracking methods.
The study analyzed 1,155 ovulatory cycles from 964 Oura Ring users, finding that the device’s physiology-based method detected 96.4% of ovulations with an average error of 1.26 days. This significantly outperformed the traditional calendar method, which showed an average error of 3.44 days.
“We prioritized designing an algorithm that works for everyone, including individuals with irregular cycles, as they often encounter the biggest hurdles with existing solutions,” says Xi Zhang, VP of Health Sensing at Oura. “Developing algorithms for irregular cycles is more challenging, but it’s also where the impact can be most significant.”
The technology showed particular strength with irregular cycles, where traditional methods often fall short. For users with irregular cycles, 82% of Oura Ring’s estimations were within two days of the reference ovulation date, compared to just 32.5% for the calendar method.
The study used data from users who confirmed ovulation through luteinizing hormone tests, comparing the ring’s temperature-based predictions against these verified ovulation dates. The algorithm maintained its accuracy across different age groups and cycle lengths, though showing slightly lower detection rates in cycles shorter than 26 days.
This validation represents a significant step for consumer wearables in fertility tracking, particularly as the study included users with irregular cycles rather than excluding them as many previous studies have done. The researchers note, however, that the study was limited to ovulatory cycles, and the algorithm is not intended for use in individuals who frequently experience anovulatory cycles or who don’t ovulate due to factors such as hormonal contraceptives.
The research suggests that wearable technology could provide a low-effort alternative to traditional fertility tracking methods, while offering comparable accuracy to cervical mucus tracking, which has historically been considered one of the more reliable methods of ovulation detection.
