Study Published in Journal of Medical Internet Research Demonstrates Ava Fertility Tracking Bracelet More Sensitive in Detecting Ovulation Than Temperature Methods

ZURICH — June 29, 2021 — Ava, a digital healthcare company that focuses on women’s reproductive health, announced today the publication of results from a clinical trial demonstrating that, for women interested in maximizing the chances of pregnancy, wrist skin temperature continuously measured during sleep is more sensitive than basal body temperature in detecting ovulation. 

The temperature method has been the gold standard for at-home identification of ovulation since the 1950s. It is used by 24 percent of women who are trying to conceive¹. Traditional temperature methods require the user to take daily manual measurements; this study demonstrates that the Ava bracelet’s more convenient method of obtaining temperature data during sleep is also more sensitive in detecting ovulation. 

The peer-reviewed paper, published in the Journal of Medical Internet Research (The Accuracy of Wrist Skin Temperature in Detecting Ovulation Compared to Basal Body Temperature: Prospective Comparative Diagnostic Accuracy Study) included 57 healthy women and 193 menstrual cycles (170 ovulatory and 23 anovulatory). Participants wore an Ava bracelet that continuously measured wrist temperature during sleep. They also measured oral temperature daily with a digital thermometer. The results showed wrist skin temperature as measured with the Ava bracelet was more sensitive than oral temperature (sensitivity 0.62 vs 0.23; P<.001) and had a higher true-positive rate (54.9% vs 20.2%) for detecting ovulation. Furthermore, a greater post-ovulatory increase in body temperature was detected using the Ava bracelet than traditional temperature methods (0.50°C v. 0.2°C, respectively). 

Temperature is just one of several physiological parameters used in Ava’s machine learning algorithms. The Ava bracelet also measures resting pulse rate, heart rate variability ratio, perfusion, and breathing rate—collecting approximately three million data points per night of use. Prior research has demonstrated that Ava detects significant, phase-based shifts in the aforementioned physiological parameters throughout a woman’s menstrual cycle to pinpoint her fertile window. 

These results validate Ava’s innovative approach of using continuous, non-invasive monitoring to provide reproductive health insights,” said Ava’s Chief Medical Officer, Dr. Maureen Cronin. “It’s not only more sensitive than traditional temperature methods—it’s also more convenient.” 

About Ava

Ava is a digital health company with offices in Zurich, San Francisco, Belgrade, and Makati that advances women’s reproductive health by bringing together artificial intelligence and clinical research. Its fertility tracking sensor bracelet detects the five most fertile days of a woman’s cycle in real-time with 90% accuracy, while also delivering personalized insight about reproductive health and pregnancy.

Worn only during sleep, the Ava bracelet* tracks multiple physiological parameters including pulse rate, breathing rate, and skin temperature. Launched in the US in 2016, the Ava bracelet is now sold in 36 countries and has helped more than 50,000 women become pregnant. Studies for the clinical use of Ava have been conducted in collaboration with academic partners around the world, including at the University Hospital of Zurich, Switzerland, Columbia University, and Northwestern University’s Feinberg School of Medicine. Ava was voted Best of Baby Tech at CES, named a Women’s Health “Editors’ Choice” product and has been honored as a CB Insights Digital Health 150 company. For more information on Ava, visit

*The Ava Fertility Tracker is the only FDA-cleared fertility tracking wearable and is also CE-marked according to MDD 93/42/EC for the purpose of measuring and displaying physiological parameters to facilitate conception and to provide general information on health and wellness to users. 

1.  Data on file, Ava survey 2019

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