Modeling Fertile Window Differences Across the Reproductive Lifespan with Quantitative Urine Hormone Monitoring of the Menstrual Cycle

Background Reproductive hormones of the fertile window are often referenced to women in regular cycles, but this may not be representative of the hormonal profiles of women in different circumstances like polycystic ovarian syndrome, the postpartum period, and the perimenopause transition. This observational cohort study sought to identify the variability in the hormones of the fertile window in various reproductive categories and to establish potential thresholds for each category based on hormone measurements with the Mira urinary hormone monitor. Results A total of 57 women (ages 22–51) in various circumstances (regular cycles, polycystic ovarian syndrome, postpartum and perimenopause) tracked Mira urine hormone measurements (estrone-3-glucuronide, luteinizing hormone, pregnanediol glucuronide), contributing 444 cycles of data. Using additive mixed models, hormone values were stratified by the four different reproductive categories. The perimenopause and polycystic ovararian syndrome groups demonstrated relative hypoestrogenic states, while the perimenopause group showed low luteal pregnanediol glucuronide and the polycystic ovarian syndrome group showed high luteal pregnanediol glucuronide. The perimenopause group had higher luteinizing hormone values throughout the whole cycle. Conclusion The fertile window hormone thresholds vary depending on a woman’s specific reproductive category. Women in different circumstances should not necessarily use the same hormonal thresholds for the fertile window and ovulation. A larger dataset with ultrasound correlation to ovulation is required to delineate the fertile window with more precision. Hormone differences across the menstrual cycle could be used for targeted treatments in polycystic ovarian syndrome and perimenopause women.