Induction of ovulation with an estrogen antagonist, tamoxifen.

Tamoxifen (Norvadex), synthesized by the Imperial Chemical Industries Ltd., is a triphenylethylene derivative having a clomiphene-like structure and displays anti-estrogenic activities. In this study we used tamoxifen for the treatment of anovulatory infertility and investigated the clinical results. Induction rate of ovulation recorded 100% in the patients with sporadic anovulatory cycle, 83.3% in those with persistent anovulatory cycle, 70% in those with the first grade amenorrhea type I and 66.7% in those with the first grade amenorrhea type II. However, tamoxifen was absolutely ineffective against the second grade amenorrhea. The patients with sporadic or persistent anovulatory cycle responded to 40 mg-daily tamoxifen-treatment, recording 100% of ovulatory induction rate. The patients with the first grade amenorrhea also responded to 60 mg-daily treatment, indicating 70% of ovulatory induction rate. The rate of pregnancy established in the women desiring pregnancy marked 15.4%, and 2 out of 4 women with successful pregnancy experienced spontaneous abortion. Out of 4 patients who did not respond to the previous clomiphene treatment, 3 women accomplished ovulatory induction with tamoxifen. The endocrinological dynamics in the tamoxifen treatment were similar to those in the clomiphene treatment.