Objective: To study the effect of clomiphene citrate (CC) on the thickness and echogenic pattern of the endometrium using vaginal sonography.
Method: In this experimental prospective study, CC was given to 31 women with unexplained infertility. Thickness and echo patterns of the endometrium, as well as estradiol (E2) and progesterone (P) levels, were compared in women taking CC and in control patients during both the late proliferative and midsecretory phases of the menstrual cycle.
Results: Endometrial thickness was significantly thinner in women taking CC (P<0.03) than in controls during the late proliferative phase but there was no significant difference during the midsecretory phase. The endometrial echogenic patterns of women taking CC who had conceived revealed endometrial thicknesses of grade III and grade IV on midsecretory days, but these findings were not significantly different from those of women who had not conceived (P=0.3). Serum E2 level was higher in women taking CC than in the controls on both late proliferative and midsecretory days (P<0.05).
Conclusion: CC affects endometrium thickness on late proliferative days but not on midsecretory days, and does not alter the echogenic pattern of the endometrium.