High dose of phytoestrogens can reverse the antiestrogenic effects of clomiphene citrate on the endometrium in patients undergoing intrauterine insemination: a randomized trial.
J Soc Gynecol Investig. 2004 Jul;11(5):323-8. PMID: 15219887
OBJECTIVE: To compare the effectiveness of clomiphene citrate (CC) alone or combined with phytoestrogens (PE) in ovulation induction in patients who had intrauterine insemination in a randomized, double-blind study. METHODS: A total of 134 women aged 25-35 years, who were infertile for at least 2 years and who had oligomenorrhea or amenorrhea associated with a positive menstrual response to the intramuscular progesterone-challenge test were enrolled. They were randomly treated with CC (100 mg daily for 5 days) and CC (100 mg daily for 5 days) in combination with PE (1500 mg daily for 10 days). We estimated the difference in uterine artery pulsatily index, number of preovulatory follicles, endometrial thickness, and pregnancy rate. RESULTS: Both treatments increased follicle-stimulating hormone, luteinizing hormone, and 17beta-estradiol plasma concentrations, but the differences were not statistically significant. However, the differences in endometrial thickness of the two groups were statistically significant. No significant differences in the pulsatility index values and in the number of preovulatory follicles were noted. CONCLUSION: A high dose of phytoestrogens can reverse the deleterious effects of clomiphene citrate on endometrial thickness and could contribute to higher pregnancy rates.