Use of ethinyl estradiol to reverse the antiestrogenic effects of clomiphene citrate in patients undergoing intrauterine insemination: a comparative, randomized study

To compare the effectiveness of clomiphene citrate used alone and in combination with ethinyl E2 for the induction of ovulation in patients undergoing IUI.

Randomized, double-blind study.

Four infertility treatment centers. PATIENT(S): Women aged 25-35 years with infertility of at least 2 years' duration and oligomenorrhea or amenorrhea associated with a positive menstrual response to an IM progesterone challenge. INTERVENTION(S): A total of 64 patients were randomized to treatment with CC (100 mg daily for 5 days) or CC (100 mg daily for 5 days) plus ethinyl E2 (0.05 mg daily for 5 days). MAIN OUTCOME MEASURE(S): The uterine artery pulsatility index, number of preovulatory follicles, endometrial thickness, and pregnancy rate. RESULT(S): Both treatment regimens increased FSH, LH, and 17beta-E2 levels, with no statistically significant differences. There was a statistically significant difference in endometrial thickness between the two treatment groups. No statistically significant differences were noted in pulsatility index values or in the number of preovulatory follicles. CONCLUSION(S): Ethinyl E2 can reverse the deleterious effects of CC on endometrial thickness, which may contribute to higher pregnancy rates.