Estradiol rose above normal before ovulation in tamoxifen cycles
Estradiol before ovulation rose above the normal range in cycles where tamoxifen brought on ovulation.After ovulation, progesterone rose and fell much as in normal cycles, with occasional values above normal. The 1983 case series took daily blood samples from 5 of 22 women given tamoxifen for cycles without ovulation. Researchers compared them with 5 normal volunteers.
Study at a glance, descriptive series of 22 women with anovulatory cycles: Estradiol rose above normal before ovulation in tamoxifen cycles. Source: Tajima C et al., 1983, PMID 6407877.
Key Findings
Twenty-two women whose cycles lacked ovulation received tamoxifen across 46 cycles. Ovulation followed in 33 of those cycles, in 16 women, and 4 of them became pregnant.
Daily blood samples came from 5 of the 33 tamoxifen-induced ovulatory cycles and were compared with 5 normal cycles. Two of the five patients conceived during the study cycle.
Follicular-phase estradiol in the five induced cycles was higher than in normal cycles. Mean luteinizing hormone was significantly lower than normal (P < 0.01), and follicle-stimulating hormone did not differ significantly.
Follicle-stimulating hormone and luteinizing hormone climbed during tamoxifen or in the days after. Estradiol then reached an extremely high preovulatory peak, which the authors say triggered the luteinizing hormone surge.
After ovulation, progesterone rose and fell as in normal cycles, with occasional values above the normal range. The authors report that luteal-phase progesterone in three cycles did not differ from normal women.
Interpretation
The paper is a descriptive series of daily hormone measurements. The series includes 5 induced cycles from 5 women and 5 normal cycles from volunteers aged 24 to 29. The authors give group means with significance values and describe each cycle one by one. The 22 women had no other known cause of infertility. The authors suggest the initial site of tamoxifen's action in inducing ovulation is the hypothalamic-pituitary axis. They state that the reason for the high estradiol, with gonadotropin levels not raised, should be investigated further.
RRM Context
In restorative reproductive medicine, ovulation is the key event of the cycle. A progesterone rise after ovulation marks an ovulatory event. The paper reports luteal progesterone in three induced cycles. Restorative care for missing ovulation asks why it is missing.
Our editorial summary of this paper, not the article's abstract.
Abstract
A group of 22 women with anovulatory cycles was treated with tamoxifen in 46 cycles. We elucidated daily hormone profiles in 5 of the 33 tamoxifen-induced ovulatory cycles in order to make a comparison with those found in 5 normal cycles. Serum follicle-stimulating hormone and luteinizing hormone (LH) rose during or a few days after the tamoxifen therapy, and thereafter serum estradiol levels rose gradually over the normal ranges during the follicular phase and reached an extremely high preovulatory peak which triggered an LH surge. This increased estradiol production exerted its usual negative feedback on LH secretion. Following ovulation, serum progesterone rose and fell in a manner similar to that in the normal cycles, with occasional values that exceeded the normal range. The endocrine significance of these findings is discussed.
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