Ecochard, R., Duterque, O., Leiva, R., Bouchard, T., & Vigil, P. (2015). Self-identification of the clinical fertile window and the ovulation period. Fertility and Sterility, 103(5), 1319-25.e3. https://doi.org/10.1016/j.fertnstert.2015.01.031
Ecochard R, Duterque O, Leiva R, Bouchard T, Vigil P. Self-identification of the clinical fertile window and the ovulation period. Fertil Steril. 2015;103(5):1319-25.e3. doi:10.1016/j.fertnstert.2015.01.031
Ecochard, Rene, et al. "Self-identification of the clinical fertile window and the ovulation period." Fertility and Sterility, vol. 103, no. 5, 2015, pp. 1319-25.e3.
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Peak mucus overlaps the 6-day fertile window in 96% of cycles
Peak mucus overlapped the 6-day fertile window in 96% of 132 cycles, meaning at least 1 fertile day. The study followed 107 women who charted daily while ultrasound tracked ovulation. The peak-mucus window averaged 4 days. Any mucus overlapped the window in every cycle and averaged 11 days.
Study at a glance, cohort study of 107 women: Peak mucus overlaps the 6-day fertile window in 96% of cycles. Source: Ecochard R et al., 2015, PMID 25724738.
Key Findings
Peak mucus included at least 1 day of the 6-day fertile window in 96% of cycles (95% CI 91–99). Any type of mucus did so in 100% of 132 cycles.
The peak-mucus window averaged 3.78 days, with a mean of 1.03 days outside the fertile window. The any-mucus window averaged 10.58 days, with a mean of 5.11 days outside.
For the 2-day ovulation window (ovulation day plus the day ahead of it), peak mucus included at least 1 day in 88% of cycles (95% CI 81–93).
All 6 fertile days fell inside the peak-mucus window in only 6% of cycles, and inside the any-mucus window in 69%.
The peak-mucus window began before the fertile window in 9% of cycles (95% CI 3–14). The any-mucus window began before it in 62% (95% CI 54–72).
Interpretation
This cohort study followed 107 women through 326 cycles, recruited in 1996 and 1997 at eight natural family planning clinics in five European countries. Participants were aged 19 to 45 with cycles of 24 to 34 days, and women with infertility or abnormal cycles were excluded, so the results describe normally fertile women. Daily ultrasound scans near ovulation set the day of ovulation and the fertile window. The authors note that accuracy may be overestimated for shorter or longer cycles, since 80% of cycles in the group fell between 25 and 32 days. The findings support larger studies of mucus-based fertile-window detection.
RRM Context
Fertility awareness-based methods teach women to read mucus as a sign of the fertile window. The authors write that methods built for avoiding pregnancy accept long windows to catch every fertile day. For couples trying to conceive, they write that fewer extra days matters more. They suggest mucus quality may deserve more attention in infertility diagnosis. Restorative reproductive medicine treats cycle charting as a source of data about ovulation.
Our editorial summary of this paper, not the article's abstract.
Abstract
Objective
To assess the sensitivity and specificity of the self-identified fertile window.
Design
Observational study.
Setting
Not applicable.
Patients
A total of 107 women.
Interventions
Women recorded cervical mucus observation and basal body temperature daily while undergoing daily ovarian ultrasound.
Main Outcome Measures
The biological fertile window, defined as the 6 days up to and including the day of ovulation; and the 2-day ovulation window, defined as the day before and the day of ovulation.
Results
The self-identification of the biological fertile window by the observation of any type of cervical mucus provides 100% sensitivity but poor specificity, yielding a clinical fertile window of 11 days. However, the identification of the biological fertile window by peak mucus (defined as clear, slippery, or stretchy mucus related to estrogen) yielded 96% sensitivity and improved specificity. The appearance of the peak mucus preceded the biological fertile window in less than 10% of the cycles. Likewise, this type of mucus identified the ovulation window with 88% sensitivity.
Conclusions
These results suggest that, when perceived accurately, more accurate clinical self-detection of the fertile window can be obtained by identification of peak mucus. This may improve efforts to focus intercourse in the fertile phase for couples with fertility concerns.
