Tajima, C. (1984). Endocrine profiles in tamoxifen-induced conception cycles. Fertility and Sterility, 42(4), 548-553. https://doi.org/10.1016/s0015-0282(16)48137-9
Tajima C. Endocrine profiles in tamoxifen-induced conception cycles. Fertil Steril. 1984;42(4):548-553. doi:10.1016/s0015-0282(16)48137-9
Tajima, Choshin. "Endocrine profiles in tamoxifen-induced conception cycles." Fertility and Sterility, vol. 42, no. 4, 1984, pp. 548-553.
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Five tamoxifen conception cycles had higher estradiol, progesterone
A 1984 case series from Japan found that tamoxifen conception cycles showed higher estradiol and higher early luteal progesterone than normal cycles. Daily blood tests covered 5 of 25 women who got pregnant on tamoxifen, plus 5 normal cycles. FSH and LH were lower before ovulation in its summary table.
Key Findings
Twenty-five infertile women conceived while taking tamoxifen: 17 with luteal phase deficiency, 4 with cycles without ovulation, 3 with irregular periods and 1 with secondary amenorrhea.
Daily blood samples came from 5 of the 25 conception cycles. The comparison group was 5 cycles from normal menstruating volunteers.
In the follicular phase, estradiol averaged higher in the tamoxifen conception cycles, while follicle-stimulating hormone and luteinizing hormone averaged lower.
Progesterone on days 6 and 7 of the luteal phase was higher in the tamoxifen conception cycles. Follicular phase progesterone showed no apparent difference.
Interpretation
This case series followed 5 tamoxifen conception cycles and 5 cycles from normal volunteers who did not conceive in those cycles. The author suggests the estradiol rise may come from a direct effect of tamoxifen on the ovary. For the higher progesterone, the author offers a tamoxifen effect on the luteal phase or an early signal from the embryo, supported by rabbit studies. The author notes further study is needed to confirm these hormone patterns in larger series.
RRM Context
Luteal phase deficiency affected 17 of the 25 women. The author defined it by a short luteal phase on basal body temperature charts and an endometrial biopsy out of phase. Progesterone after ovulation is one marker of luteal function. Restorative reproductive medicine uses fertility awareness charting to find the cause of a short luteal phase. The paper reports hormone patterns in 5 of the 25 women during tamoxifen treatment.
Our editorial summary of this paper, not the article's abstract.
Abstract
Twenty-five infertile women conceived while taking tamoxifen (TMX). Daily serum profiles of 5 of the 25 TMX-induced conception cycles were elucidated and compared with those found in 5 normal cycles. In spite of lower levels of follicle-stimulating hormone and luteinizing hormone during the follicular phases, estradiol concentrations were higher in the TMX-induced conception cycles. It is suggested that this may be due to a direct ovarian effect of TMX as one of its major mechanisms in the course of folliculogenesis. On the other hand, progesterone concentrations on days 6 and 7 during the luteal phases were also higher in the TMX-induced conception cycles. It is suggested that this may be due to a luteotropic influence at the blastocyst stage.
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