By: 15 May 2017
How a women’s resting pulse rate can be used to  identify the beginning of her fertile window

Ava, a medical technology company focused on innovations in women’s reproductive health, has announced the publication of the first findings from its recent clinical trials proving evidence of a significant increase — an average of two beats per minute — in resting pulse rate at the beginning of the fertile window compared to the menstrual phase.

The significance of these findings – which appear in the May issue of Scientific Reports, a peer-reviewed journal from the Nature Publishing Group – is that resting pulse rate can be used to identify the beginning of the fertile window in real time. In combination with temperature and other supporting parameters, the Ava bracelet detects the five most fertile days of a woman’s cycle. Other currently available methods of fertility tracking such as LH ovulation strips can only identify the last 12 – 24 hours of fertility, and those reliant soley on basal body temperature recognise only the day after ovulation, when the fertile window is already over.

“What many women and their partners don’t realise is that a woman can only get pregnant five days before ovulation and the day of ovulation itself,” explained Brigitte Leeners, the fertility and women’s reproductive health expert who led the studies at the University Hospital of Zurich.

“In our research, we found that resting pulse rate usually is lowest during menstruation but rises significantly five days before ovulation and again after ovulation. Ava is the first technology that uses temperature, resting pulse rate, and other parameters, including heart rate variability, sleep and bioimpedance, to provide a convenient and accurate at-home method to identify the beginning of the fertile window.”

“We are committed to advancing the technology of women’s health tracking and deepening scientific understanding of the menstrual cycle through clinical research. Ava is an innovative way to detect more fertile days, earlier within a woman’s cycle, compared to other methods,” said Peter Stein, Ava Co-Founder and Vice President of Research and Development.


Ava’s pulse rate findings are the result of two separate prospective observational trials. Data from a total of 91 women with these trials were included in the final paper published by Scientific Reports. Both trials were led by Prof. Leeners at the University Hospital of Zurich. Pulse rate was measured during sleep using photoplethysmographic (PPG) sensors.

Ava’s goal with the research was to find out whether it was possible to use wrist-worn wearable sensors to give women an accurate, convenient, at-home method of predicting ovulation. The clinical study concluded that temperature and resting pulse rate can be used along with several other parameters to precisely detect the fertile window. Resting pulse rate increases at the beginning of the fertile window and continues to increase after ovulation, reaching a peak in the mid-luteal phase (when it is 3.5 beats higher than during the menstrual phase).

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