The effect of ethinyl estradiol on endometrial thickness and uterine volume during ovulation induction by clomiphene citrate

Abstract

Objective: To assess the deleterious effect of clomiphene citrate (CC) on the development of the endometrium and its improvement by the addition of ethinyl estradiol (E2). PARTICIPATING PATIENTS: Infertility-treated patients, monitored for induction of ovulation or timing of insemination (control group).

Design: We studied four groups of women during an ovulatory cycle with various treatment schedules. Group 1: untreated patients; group 2: patients treated by CC; group 3: patients treated by CC + ethinyl E2; group 4: patients treated by human menopausal gonadotropin. Follow-up of the patients was done by vaginal ultrasonography and measurements of blood E2.

Results: In the group treated by CC, both endometrial thickness and uterine volume growth during the follicular phase were lower as compared with untreated controls and menotropin-treated patients. The addition of ethinyl E2 to these patients reversed this deleterious effect of CC without interfering with ovulation.

Conclusion: Ethinyl E2 may reverse the deleterious effect of CC on endometrial development during the follicular phase.