Objective: To study the effects of clomiphene citrate (CC) on the endometrium by ultrasound and to reveal the echogenic difference between the control cycle and the CC cycle.
Design: Retrospective study of patients before and during a CC treatment.
Setting: Department of Obstetrics and Gynecology, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.
Patient(s): Seventy-nine infertile women who had a spontaneous ovulation and a normal luteal function.
Intervention(s): Patients received 50 mg/d CC between days 5 and 9 of the menstrual cycle.
Main outcome measure(s): Endometrial thickness, echogenic pattern of the endometrium, serum E2 content, and E2 and P receptor contents in the endometrium.
Result(s): Endometrial thickness was significantly thinner during the CC cycle (7.6 +/- 1.4 mm, mean +/- SD, n = 79) than during the control cycle (8.5 +/- 1.7 mm, n = 79) on late proliferative days, but there was no significant difference on midsecretory days (10.8 +/- 2.2 mm during the CC cycle, n = 79; 11.2 +/- 2.2 mm during the control cycle, n = 79). The echogenic patterns, however, were different between the two cycles on midsecretory days. Moreover, the incidence in which patients showed a grade 3 endometrium on midsecretory days was significantly higher during the conceived CC cycle compared with the not-conceived CC cycle. Serum E2 levels were significantly higher, but E2 receptor contents in the endometrium were significantly lower during the CC cycle (67 +/- 46 fmol/mg, n = 13) compared with the control cycle (123 +/- 89 fmol/mg, n = 15) on late proliferative days.
Conclusion(s): Clomiphene citrate affected the echogenic pattern of the endometrium, and most of the endometrium showed a grade 3 pattern on midsecretory days during the conceived CC cycle. Under the CC treatment, the comfortable endometrium for embryos might be different from the control cycle.