Inclusion Criteria:  Patients with Clomiphene Citrate resistant PCOS who fulfilled the following inclusion criteria:  Age 18 to 35 years Body mass index (BMI) between 18.5 and 34.9 kg/m2 Presenting with primary or secondary infertility.  PCOS was diagnosed according to the Rotterdam ESHRE/ASRM Consensus workshop, with at least 2 of the following 3 criteria:  A- Oligo- and/or anovulation; manifested by oligomenorrhea or amenorrhea. Oligomenorrhea was defined as cycle interval of more than 35 days but less than six months. Amenorrhea was defined as absence of menstruation for six months or more.  B- Hyperandrogenism; biochemical and/or clinical in the form of acne or hirsutism defined as a score of 8 or higher using the modified Ferriman-Gallwey scoring system when abnormal hair distribution was assessed in nine body areas and given a score of 0 to 4.  C - Polycystic ovarian morphology detected by transvaginal ultrasound with the presence of 12 or more follicles measuring 2-9 mm in diameter in one or both ovaries, and/or increased ovarian volume >10 mL.  Clomiphene Citrate resistance was defined as failure of ovulation after administration of Clomiphene Citrate in a dose of 150 mg for 5 days per cycle, for two or three cycles. Patent both fallopian tubes and normal uterine cavity as evidenced by hysterosalpingography (HSG). Their partners had normal semen parameters as defined by the modified WHO 2010 criteria.  Exclusion criteria were:  Morbidly obese patients with BMI ≥35 Kg/2m. Abnormal husband semen analysis. Abnormal HSG or laparoscopic evidence of pelvic adhesions. Patients receiving statin drugs for cholesterol, beta-blockers for high blood pressure, or tricyclic antidepressants, were also excluded as these drugs can lower the levels of ubiquinol in the body.