Maxson, W. S., Pittaway, D. E., Herbert, C. M., Garner, C. H., & Wentz, A. C. (1984). Antiestrogenic effect of clomiphene citrate: correlation with serum estradiol concentrations. Fertility and Sterility, 42(3), 356-359. https://doi.org/10.1016/s0015-0282(16)48072-6
Maxson WS, Pittaway DE, Herbert CM, Garner CH, Wentz AC. Antiestrogenic effect of clomiphene citrate: correlation with serum estradiol concentrations. Fertil Steril. 1984;42(3):356-359. doi:10.1016/s0015-0282(16)48072-6
Maxson, Wayne S., et al. "Antiestrogenic effect of clomiphene citrate: correlation with serum estradiol concentrations." Fertility and Sterility, vol. 42, no. 3, 1984, pp. 356-359.
For EndNote, Zotero or Mendeley:
License
No open license is recorded for this paper. Reuse terms are set by the publisher.
High-dose clomiphene lowered cervical mucus in ovulatory women
A 1984 study compared drug cycles with natural cycles in 49 women who ovulated but were infertile. High-dose clomiphene citrate lowered cervical mucus scores, even with much higher estrogen. On the day estrogen peaked, scores averaged 4.1 with the drug and 6.9 without.
Key Findings
On the day of peak estradiol, the mean cervical mucus score was 4.1 with clomiphene citrate and 6.9 in untreated control women (P < 0.01), on a scale of 0 to 9.
Estradiol was higher in the clomiphene cycles throughout the periovulatory period (P < 0.0001).
In natural cycles, mucus scores rose in a linear fashion as estradiol rose. In clomiphene cycles, scores stayed depressed until the day of peak estradiol.
The study followed 49 infertile women aged 25 to 41 with ovulatory cycles: 25 in natural cycles and 24 given clomiphene citrate.
Interpretation
The study compared two groups of women at one university center. One examiner scored the mucus each day, which keeps scoring consistent but is still a subjective judgment. The women already ovulated, and the dose was high. Women with irregular ovulation or lower doses may respond differently. The authors did not test whether sperm could get through the mucus, so effects on conception were not measured.
RRM Context
Cycle-charting methods such as the Creighton Model read cervical mucus as a sign of the body's own estrogen activity. In this study, clomiphene citrate pulled the two apart: estradiol rose while mucus scores fell. Mucus seen during clomiphene cycles would track estrogen less closely than in natural cycles.
Our editorial summary of this paper, not the article's abstract.
Abstract
The antiestrogenic effect of clomiphene citrate (CC) on cervical mucus was evaluated in women receiving 150 mg CC daily for 5 days. Daily cervical mucus scores and serum estradiol (E2) concentrations were determined in control (n = 25) and CC (n = 24) cycles. E2 concentrations were significantly higher in the CC-treated women (mean +/- standard error of the mean, 1254 +/- 102 pg/ml versus 337 +/- 18 pg/ml, P less than 0.0001). Despite supraphysiologic E2 concentrations, however, cervical mucus scores were significantly reduced in the CC-treated group (P less than 0.01). These data indicate that CC exerts a direct suppressive effect on cervical mucus despite markedly increased E2 concentrations.
