The proposal of This study approved by our institutional review boards and institution's ethical committee, and all Participants will sign a written consent before enter to study. All patients will be randomly divided into two groups, A and B. Stimulation will begin on day 3 with the administration of 100 mg of clomifen citrate(CC) daily for 5 days. On day 8, ethinyl estradiol will be given daily for 5 days in group A and placebo will be given for 5 days in group B. Plasma levels of estradiol(E2), Luteinizing hormone (LH) and Follicle-stimulating hormone (FSH) will be evaluated on days 3 and 13 of the menstrual cycle. Ultrasound examination will be done on days 3, 13 and days of HCG administration and IUI for determining of endometrial thickness, number of follicles and size of the dominant follicle.