According to the studies CC is successful at inducing ovulation in 50%-75% of cases, but only 30-40% becomes pregnant. The difference has been attributed to a negative action of clomifen citrate(CC) in the form of prolonged antiestrogenic effects on endometrial receptivity. For avoiding of these negative effects, giving ethinyl estradiol in sufficient dosages may be effective. The purpose of this study is comparing pregnancy rates after IUI in women who use CC alone and those who use CC in combination with ethinyl estradiol

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.

When the diameter of at least one follicle reached equal or greater than 18 mm, human chronic gonadotrophin (HCG) 10,000 IU will be administered.

The pulsatility index also will be recorded in both uterine arteries on day of HCG administration. A single IUI will be performed 24-36 hours after the administration of hCG. Pregnancy will be confirmed by increasing level of concentration of serum βHCG which will be assessed 14 days after IUI

Inclusion Criteria:

• The patients with first treatment cycle
• Age between 25 and 30 years,
• Infertility for at least 2 years' duration,
• Oligomenorrhea or amenorrhea associated with a positive Progesterone challenge test
• Women with normal concentrations of prolactin, free thyroxin and thyroid-stimulating hormone (TSH)

Exclusion Criteria:

• Women whose partners had an abnormal semen analysis according to World Health Organization
• Women who had uterine or tubal abnormalities on hysterosalpingography, and women who had a body mass index of >30 kg/m2.