Background: Measuring quantitative menstrual cycle hormones at home may help women better understand their postpartum and perimenopause fertility transitions, but these quantitative fertility monitors require validation. Materials and Methods: This study included 16 North American women, aged 28–51, during either the postpartum (n = 8, cycles = 18) or perimenopause (n = 8, cycles = 35) fertility transitions testing daily firstmorning urine testing with both the Mira Monitor and ClearBlue Fertility Monitor (CBFM) along with menstrual cycle parameter tracking. The main outcome measures were a rise in estrone-3-glucuronide (E 1 3G) and luteinizing hormone (LH) urine hormone values from the Mira monitor correlated to low, high, or peak values on the CBFM. Results: Both in the postpartum and perimenopause transitions, the identification of the day of ovulation based on the LH surge on the Mira and CBFM monitors was highly correlated (R = 0.94 and 0.83, p < 0.001). The E13G levels on the Mira monitor were significantly higher for a CBFM reading of “High” compared with “Low” for both the postpartum and perimenopausal cycles (all p < 0.001). Similarly, the LH levels on the Mira monitor were significantly higher for a CBFM reading of “Peak” (LH surge) compared with “High” for both the postpartum and perimenopausal cycles (all p < 0.001). Conclusions: The LH surge and levels of E 1 3G in urine identified on the quantitative Mira fertility monitor strongly correlate to the LH surge and the shift from low to high on the CBFM during the postpartum and perimenopause transitions.