How Priya uses Continuous Core Temperature to Find the Fertile Window

For over 100 years, we have known that we ovulate once a month. And since that time, we have tried to capture this crucial moment to conceive by peeing on sticks, measuring cervical fluid, tracking basal body temperature, and looking at the shape of our saliva under a microscope. Yet, with all the advances in ovulation predictor products, many women still feel that the options are cumbersome and unreliable. Plus, all the methods currently available only ‘estimate’ when we are most fertile.

Science shows that there is a biomarker that can tell us precisely when we are most fertile. Which is not the day we ovulate, but two days before.  Technology is advancing in every category of our lives, so what about our fertility? Can technology today notify us when we are most fertile? Yes, and the product is called Priya. 

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Why Measure Continuous Core Temperature?

Oral and skin temperature measurement can be affected by external cues.  Not feeling great? Not sleeping well? These types of everyday factors can impact peripheral temperature readings. Continuous core temperature, on the other hand, is not affected by any external cues and is capable of detecting subtle pattern changes in temperature that predict ovulation. Priya, therefore, is not affected by movement, drink, medications, and other external factors that other ovulation products are prone to - making it possible to precisely identify your fertile window. 


Our bodies tightly control body temperature and exhibit a striking diurnal temperature pattern. A pre-ovulatory decline in core temperature (aka dip in temperature before ovulation) takes place 24-48 hours prior to ovulation (1,2). What this means is that if we can accurately capture continuous core temperature, we can predict impending ovulation. In fact,  algorithms using core temperature have achieved a 99% sensitivity for detection of ovulation, with a 99% percent accuracy.

How Priya uses Continuous Core Temperature to Find the Fertile Window

So, how does Priya capture the elusive dip in temperature to predict ovulation using continuous core temperature? Priya is a vaginal ring that you simply insert at home. There are no monitors, attachable extra sensors, urine strips, or replacement parts. All that is required is to pair the Priya Ring with the Priya App and insert the ring. Once inserted, Priya captures your core temperature 24-7 and uses an algorithm to notify you on your smartphone when you are most fertile, allowing for you to go about life as normal. 

By wirelessly capturing continuous core temperature, Priya provides a level of precision that no other ovulation prediction method can obtain.  


Priya by Prima-Temp is here to put your fertility back into your control by taking out the guesswork. We want to give you the greatest chance of creating a little human of your own.

Our mission is technology to transform health care. Read more about Prima-Temp's products, our story and how we plan to improve lives by using continuous core temperature. 


  1. Coyne et al. (2000). Circadian Rhythm Changes in Core Temperature over the Menstrual Cycle: Method for Noninvasive Monitoring Physiol Regulatory Integrative Com Physiol. AM J 279:1316-132.
  2. Cagnacci et al. (1997). Regulation of the 24-hour Rhythm of Body Temperature Cycles with Spontaneous and in Menstrual Gonadotropin-induced Ovulation.Fertility and Sterility 68:421-425.