Effects of clomiphene citrate on the endometrium of regularly cycling women

OBJECTIVE: To study the effects of clomiphene citrate (CC) on the endometrium of regularly cycling women. DESIGN: Prospective, controlled study. SETTING: Department of Obstetrics and Gynaecology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. PATIENT(S): Thirty healthy, regularly cycling, female volunteers. INTERVENTION(S): All volunteers were studied for two consecutive cycles, one control cycle and one CC-treated cycle. Clomiphene citrate (100 mg/d) was given on days 3-7 of the CC-treated cycles. Ultrasonography was performed daily to assess ovulation. Ultrasonography and endometrial biopsy were performed, and blood samples were obtained for determination of E2 and progesterone levels 7 days after ovulation in both the control and CC-treated cycles. MAIN OUTCOME MEASURE(S): Histologic dating, morphometric analysis, and ultrasonographic appearance and thickness of the endometrium. RESULT(S): Histologic dating and ultrasonographic appearance and thickness of the endometrium were similar in the control and CC-treated cycles, but morphometric parameters were different. The number of glands per square millimeter and the mean diameter of the glands were lower in the CC-treated cycles than in the control cycles, but the number of vacuolated cells per 1,000 glandular cells was higher. CONCLUSION(S): Clomiphene citrate has effects on the endometrium of regularly cycling women, as demonstrated by a reduction in glandular density and an increase in the number of vacuolated cells.