To evaluate the effect of oral Phytoestrogen or Isosorbid mononitrate or N-acetyl cysteine as an adjuvant to clomiphene citrate on induction of ovulation and pregnancy outcomes in patients with PCOS. In this three-arm open RCT, 240 PCOS infertile women were randomly divided to 3 groups for induction of ovulation. Group A, [PE group, n= 80] patients received CC 100mg/d plus oral Phytoestrogen120 mg/ day and patients in Group B, [ISMN group, n=80] received CC 100 mg/d plus 20 mg Isosorbid mononitrate and Group C, [NAC group, n=80] patients received CC 100 mg/d plus NAC 1200 mg/day.

Inclusion Criteria:

1. All patients have PCOS.
2. All patients received CC 100 mg/day for 5 days starting from day 5 with successful ovulation as documented by folliculometry and midluteal serum progesterone with no pregnancy achieved.
3. All patients have patent fallopian tubes by Hysterosalpingography.
4. Their husbands have normal semen analysis according to the modified criteria of WHO.
5. All patients have normal serum prolactin and thyroid profile.
6. Any patient having vaginitis was treated before starting induction.

Exclusion Criteria:

1. Other causes of infertility than anovulation.
2. Diabetes or other endocrinological disorders.
3. Age > 40 years.
4. Smoking.
5. Alcohol use.
6. Presence of ovarian cyst >2cm on the second day of the cycle.
7. Patients who have received gonadotrophins in the preceeding 6 months.
8. Patients who have done unilateral or bilateral ovarian drilling.
9. Allergy to PE, NO donors or NAC