The first study on Natural Cycles was aimed to evaluate the capability of the algorithm to identify ovulation and subsequently the fertile window.
The study was a retrospective study and was performed on 1501 cycles of 317 women aged 18 to 39 years. Women entered their basal body temperatures, ovulation test results and date of menstruation into the application.
Results showed that the mean delay from the first positive ovulation test to the temperature-based estimation of the ovulation day was 1.9 days; the length of the luteal phase varied on average by 1.25 days per user. Only 0.05% of non-fertile days were falsely attributed and found within the fertile window.
Please read more: http://informahealthcare.com/doi/abs/10.3109/13625187.2014.988210 or download the article below.