Women with any degree of irregularity in cycle length and/ or ovulation timing will struggle with standard basal body temperature (BBT) measurement, and products which measure other types of external temperature. That’s because there is too much variation in the temperature signal to produce an accurate representation of the action of progesterone on the ovaries – which is the signal we are trying to measure to see whether ovulation is about to occur or has occurred. The OvuSense reading is more accurate because it is taken from multiple overnight measurements in the vagina, and because the OvuSense algorithm is intelligently filtering the data to provide the truest representation of the action of progesterone on the ovaries. You should also be aware that a vaginal temperature is generally up to two degrees Celsius higher than an oral temperature reading, and higher still than other external temperature readings (such as those taken under the armpit or on the skin).

As a result of measuring in the vagina and the filtering by the algorithm, your OvuSense temperature reading will therefore very rarely be the same as any other device you are using, and if you type the OvuSense temperatures into a fertility tracker app that will also produce a different (and most likely inaccurate) result because it is set up to give results based on a different method of temperature measurement.

Papaioannou S, Delkos D, Pardey J (2014) shows OvuSense has a 99% accuracy for the detection of the date of ovulation, whereas trials for other temperature based systems show an accuracy of around 80% for detection of the date of ovulation: Freundl et. al. (2003), Rollason et al. (2014). Papaioannou S, Delkos D, Pardey J (2014) also shows OvuSense has an 89% accuracy for the prediction of ovulation in real time. No other temperature methods have a reported ability to predict the onset of ovulation in real time.