Morishita, H., Hashimoto, T., Mitani, H., Tanaka, T., Higuchi, K., & Ozasa, T. (1979). Cervical mucus and prediction of the time of ovulation. Gynecologic and Obstetric Investigation, 10(4), 157-162. https://doi.org/10.1159/000299936
Morishita H, Hashimoto T, Mitani H, Tanaka T, Higuchi K, Ozasa T. Cervical mucus and prediction of the time of ovulation. Gynecol Obstet Invest. 1979;10(4):157-162. doi:10.1159/000299936
Morishita, H., et al. "Cervical mucus and prediction of the time of ovulation." Gynecologic and Obstetric Investigation, vol. 10, no. 4, 1979, pp. 157-162.
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Clear mucus onset came about 2 days before the LH peak on average
Clear cervical mucus began increasing an average of about 2 days before the luteinizing hormone (LH) peak in 12 women. This 1979 study followed women with normal ovulation for 17 cycles. Mucus and blood were sampled daily around midcycle. The authors conclude the first day of increasing clear mucus can predict the time of ovulation in these women.
Key Findings
The study followed 12 women with normal ovulation, aged 22 to 32 years (mean 27 years), across 17 menstrual cycles.
Increasing quantities of clear cervical mucus (IQCCM) began a mean of 1.4 ± 0.2 (SE) days before the estradiol peak, ranging from 1 to 2 days.
The LH peak occurred a mean of 1.8 ± 0.2 (SE) days after IQCCM began, with a range from 1 to 3 days.
In 8 of the 12 women, IQCCM began 2 days before the LH peak.
Basal body temperature was biphasic in all cycles, and its significant rise came 2 days after the LH peak.
Interpretation
The study is a small observation from one center in 12 healthy women with normal ovulation. Researchers aspirated mucus from the cervical canal with a syringe each day around midcycle. Onset was the first day with 0.1 ml or more of clear mucus. Ovulation was inferred from hormone peaks and temperature. The authors cite earlier work placing it about 16 hours after the LH peak. The authors describe no direct confirmation of ovulation. All the women had normal ovulation, and women with irregular cycles or fertility problems were not studied.
RRM Context
Fertility awareness-based methods (FABMs) chart cervical mucus as a cycle sign. A clinician measured the mucus in this study. The paper links the mucus change to the hormone rise and leaves open how a woman's own daily observation performs. Restorative reproductive medicine treats cycle signs as information about how the reproductive system functions.
Our editorial summary of this paper, not the article's abstract.
Abstract
12 normal ovulatory women were studied during 17 menstrual cycles. The first day on which the women had increasing quantities of 0.1 ml or more clear cervical mucus (IQCCM) was closely related to the time of ovulation as monitored by basal body temperature and radioimmunoassay of serum-luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone. The results show that the time of ovulation can be predicted clinically without specialized tests by observing the day of onset of IQCCM.
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