Inclusion Criteria:  Women who have a history of infertility ≥1year. Ages between 20 and 35 years.  Patients diagnosed with PCOS according to the revised 2003 Rotterdam consensus and met 2 out of 3 criteria as follows (Rotterdam, 2004):  Oligo- and/or anovulation. Biochemical and/or clinical evidence of hyperandrogenism. Polycystic ovarian morphology on ultrasound (the presence of ≥12 antral follicles (≤9mm) and/or ovarian volume >10mL on transvaginal ultrasonographic scanning).  Other etiologies of hyperandrogenism and ovulatory dysfunction will be excluded, including androgen-secreting tumors, congenital adrenal hyperplasia, hyperprolactinemia and thyroid disease.  Exclusion Criteria:  Endometriosis grade 3 or higher. Documented ovarian failure, including basal FSH above 10IU/L. Clinically significant systemic disease, or other endocrine disorders, including 21-hydroxylase deficiency, uncorrected thyroid disease or suspected Cushing's syndrome. Patients who in the previous 3 months received hormonal treatments or other medications known to affect reproductive function, including oral contraceptives and GnRH agonists. Documented history of ovarian surgery including laparoscopic ovarian drilling, ovarian endometrioma stripping and unilateral oophorectomy Previous diagnosis of congenital (septate uterus, duplex uterus, uterus bicornis and uterus unicornis) or acquired (intrauterine adhesion, submucosal myomas and adenomyosis) uterine anomalies History of recurrent spontaneous abortion, defined as three or more previous spontaneous pregnancy losses Abnormal chromosomal karyotype in either of the partners. Inability to comply with the study procedures.