The purpose of this study is to compare the effectiveness of low dose human chorionic gonadotropin (HCG) in combination with clomiphen citrate to induce ovulation and its endocrine response in patients who had previously failed to ovulate on clomiphen citrate alone. The investigators will also compare the effectiveness and endocrine response of this approach with the regimen of adding HMG to clomiphen citrate.

Infertile women with PCOS, who have showed resistance to Clomiphen Citrate (150 mg- 5 days) in a previous IUI treatment cycle at Royan Institute (Infertility and Reproductive Medicine Research Centre) will enroll in this prospective randomized clinical trial study and will randomly be divided into three groups.

The study protocol will be assessed by an independent institutional review board and Royan ethics committee. All subjects will be given the written informed consent.

Control group (CC/hMG) will receive the 100 mg CC on days 3 to 7 of that cycle but will receive 150 mg human menopausal gonadotropin (HMG) during days of 7, 8, and 9. One of experimental Group (group B) will receive a 100 mg dose of CC but will receive a 200 IU Human chorionic gonadotropin (hCG; Choriomon; IBSA, Switzerland) intramuscular injection daily when the largest follicle is 12 mm or larger mean diameter. Other experimental group (Group C) will receive a 100 mg dose of CC but will receive a 200 IU Human chorionic gonadotropin (hCG; Choriomon; IBSA, Switzerland) intramuscular injection daily From day 9(without attention to follicle size). In both experimental groups HCG administration will be continued until the largest follicle is 18-20 mm.

Ultrasound measurements of follicle number and growth, ovulation, gestational sac, and serum hormonal levels will be recorded and compared between two groups.

Inclusion Criteria:

• Women with PCOS diagnosed by the Rotterdam criteria
• Previously documented dominant follicle or follicles (R12 mm mean diameter) on transvaginal Ultrasound follicular monitoring while receiving CC at the 150-mg dose in our clinic but have failed to ovulate;
• Primary infertility
• Documented normal uterine cavity and patent tubes by either hysterosalpingogram or laparoscopy and hysteroscopy;
• Male partner had to have a normal semen analysis by World Health Organization criteria.

Exclusion Criteria:

• previous history of IVF or ICSI treatments.
• History of hormonal treatment within recent three month (Except OCP, progesterone).
• History of ovarian cutter or Ovarian drilling.
• BMI higher than 30.
• The presence of ovarian cyst (more than 30 mm) during third cycle ultrasound.