Porucznik, C. A., Cox, K. J., Stanford, J. B., & Schliep, K. C. (2014). Pilot test and validation of the peak day method of prospective determination of ovulation against a handheld urine hormone monitor. BMC Women's Health, 14(1), 4. https://doi.org/10.1186/1472-6874-14-4
Porucznik CA, Cox KJ, Stanford JB, Schliep KC. Pilot test and validation of the peak day method of prospective determination of ovulation against a handheld urine hormone monitor. BMC Womens Health. 2014;14(1):4. doi:10.1186/1472-6874-14-4
Porucznik, C. A., et al. "Pilot test and validation of the peak day method of prospective determination of ovulation against a handheld urine hormone monitor." BMC Women's Health, vol. 14, no. 1, 2014, pp. 4.
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Cervical fluid matched urine monitors within 3 days in 24 of 26 cycles
In a 2014 pilot and validation study, the best quality algorithm for charting cervical fluid matched urine monitoring within 3 days in 24 out of 26 cycles. The 58 women analyzed learned the Peak Day method from a brochure and picked their own ovulation day in most cycles.
Key Findings
Across 147 cycles, women selected an estimated day of ovulation in 130 cycles (88%) and completed the periovulatory exposure questionnaire in 122 of those cycles (94%).
Among 110 cycles using the last fertile sign algorithm, the day women chose matched expert review exactly in 84 cycles (76%) and within 3 days in 102 cycles (93%).
Among 20 cycles using the best quality algorithm, the day women chose matched expert review exactly in 18 cycles (90%) and within 2 days in all 20 cycles (100%).
Against a blinded urine hormone monitor in 26 cycles, the best quality algorithm identified ovulation within 3 days in 24 cycles (92%) and within 1 day in 17 cycles (65%).
The last fertile sign algorithm, with the seven days before menses excluded, placed ovulation within 3 days of the monitor in 20 of 26 cycles (77%), lower than the best quality algorithm.
Interpretation
This prospective pilot and validation study enrolled women aged 18 to 44 who were not using hormonal contraception, most of them non-Hispanic white and college educated. Each woman contributed a mean of 3.2 cycles after learning the Peak Day method from a three-page brochure. Blinded expert reviewers selected a day of ovulation from each chart for comparison with the woman's own choice and, in the validation cycles, with a urine hormone monitor. The authors describe the method as suited to women of normal fertility. They note a limited number of cycles for the monitor comparison and call for further research on direct use of the best quality algorithm.
RRM Context
Cervical fluid observation is a core observation in Creighton Model FertilityCare System charting, which uses the same three fluid characteristics as the Peak Day method. Other fertility awareness-based methods also rely on it. Cycle-charting-informed RRM clinicians read daily observations as a record of when ovulation occurs. The Peak Day results add evidence that self-recorded cervical fluid tracks the timing of ovulation.
Our editorial summary of this paper, not the article's abstract.
Abstract
Background
Transient exposures may influence fertility and early embryonic development. To assess the time of conception in vivo and conduct concurrent biomonitoring, ovulation must be identified prospectively. We report on the development and validation of a simple, prospective method, the Peak Day method, to determine likely day of ovulation based upon daily observations of cervical fluid.
Methods
We recruited 98 women to learn the Peak Day method from a brochure, 26 of whom concurrently used the method with blinded daily urine hormone monitoring (estrone glucuronide and luteinizing hormone). All women were instructed to complete an exposure questionnaire immediately upon identifying ovulation. Briefly, the exposure questionnaire captured time-varying and transient exposures such as medication use, water consumption, and amount of sleep. We assessed timely completion of the exposure questionnaire, agreement of women's estimated day of ovulation (EDO) and the EDO by expert review, and agreement between the EDO by expert review and by blinded urine monitoring.
Results
Of 147 cycles evaluated, women selected an EDO in 130 (88%) and subsequently completed the periovulatory exposure questionnaire in 122 (94%) cycles. Of the 26 cycles evaluated with blinded hormonal monitoring, the Peak Day "best quality" algorithm, based upon cervical fluid, identified ovulation ± 3 days of the urine monitor in 24 cycles (92%).
Conclusions
With simple written instructions, women can identify an estimated day of ovulation and perform periovulatory exposure assessment. The Peak Day method is highly cost-effective and could be applied by researchers to target periconceptional or very early developmental stage exposure assessment.
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