Early progesterone rise in the follicular phase: predictor of anovulation?

This study investigated the role of progesterone levels during the follicular phase. While estradiol and luteinizing hormone are commonly used in evaluating the follicular phase, progesterone is not typically considered until after ovulation in the luteal phase. However, previous studies have noted a rise in progesterone prior to ovulation1,2. We further explored this phenomenon using an at-home quantitative platform to analyze progesterone patterns during the follicular phase. 1,617 women were included in this study, and 4,209 cycles were evaluated. All participants used Oova, a home-based hormone testing platform, which collects demographic information, self-reported clinical information, and daily quantitative urinary measurements of luteinizing hormone (LH) and progesterone. Oova pairs urine-based lateral flow quantitative and multiplexed immunoassay technology with AI-enabled image processing via a smartphone camera. An excellent correlation was found between urinary and serum levels (publication forthcoming). Cycle information was compiled for all users, including number of cycles tracked, cycle length, and average number of measurements obtained per cycle. Hormone data was used to classify cycles as ovulatory or anovulatory. A cycle was considered ovulatory if an LH peak above 35 mIU/L was detected, and a progesterone rise of at least 6.5 ng/mL post-LH peak. The study's results showed that the average progesterone peak during the follicular phase was 5.227 ng/mL and remained elevated for an average of 3.278 days. The average progesterone peak did not differ significantly between ovulatory and anovulatory cycles. However, the timing of the progesterone rise showed promise as a potential indicator of whether a cycle would be ovulatory or anovulatory. Anovulatory cycles had an earlier progesterone rise in the follicular phase, leading to a longer gap between the progesterone rise and LH peak (mean of 6.05 days). In contrast, ovulatory cycles had a progesterone rise occur on average 3.37 days prior to LH peak. This timing difference was statistically significant (p < 0.05), suggesting that the timing of progesterone during the follicular phase could serve as a predictive marker for ovulatory cycles. These results highlight the need to accurately monitor progesterone levels earlier in the cycle in patients trying to conceive. By understanding the progesterone activity in the follicular phase, an accurate prediction can be made on whether a cycle will be ovulatory or anovulatory. While excessive blood tests may not be preferred, home monitoring through urinary testing is a user-friendly tool to monitor cycles.