All Vietnamese, infertile women, with PCOS according to the Rotterdam criteria present at IVFMD Tan Binh and IVFMD Phu Nhuan will be enrolled to the study. Phenotypes of PCOS are classified into A, B, C and D due to hyperandrogegism (HA), ovulatory dysfunction (OD) and polycystic ovarian morphology (PCOM)

- A: HA + OD + PCOM

- B: HA + OD

- C: HA + PCOM

- D: OD + PCOM

All patients enrolled in this study will have:

- Standard anthropometric data will be done by professional and experience physicians according to standard study protocol: Weight, height, waist and hip circumference, waist to hip ratio, BMI calculated, followed by World Health Organization guidelines for Asian women.

- Blood pressure

- Fat mass measure by specific caliper which are available at the clinic. Fat mass index (FMI) are classified as: deficit < 5, normal 5-9, excess female >9-13, obese >13

- Gynecologic ultrasound scan

- Blood tests:

- Hormonal profile evaluation: Luteinizing hormone (LH) (Roche Cobas e411, S: 25.816 mIU/mL, CV: 5.8%), Follicle-stimulating hormone (FSH) (Roche Cobas e411, S: 25.045 mIU/mL, CV: 5.8%), Estradiol (Roche Cobas e411, S: 210.390 ng/L, CV: 6.6%), Total testosterone, SHBG, androstenedione, TSH (Beckman Access - S: 2,712 ng/dL, CV: 5.6%), Total triiodothyronine (total T3) (Beckman Access - S: 7.284 pg/mL, CV: 6.1%), Free thyroxine (free T4) (Beckman Access - S: 2.712 ng/dL, CV: 5.6%), Prolactin (Roche Cobas e411 - S: 37.993 mcg/L, CV: 5.5%), Progesterone (Roche Cobas e411, S:10.553 ng/mL and CV: 5.4%),17(OH)-progesterone (Elisa, DRG International, S: 0.03 ng/ml and CV: 5.8-9.2%), Free androgen index (FAI) = Serum testosterone (nmol/L)/serum SHBG (nmol/L) × 100, HDL, LDL, Fasting serum insulin (Roche Cobas e411 - S: 1.39 pmol/L, CV: 1.4%), Insulin sensitivity is estimated by homeostasis model assessment of insulin resistance (1/HOMA-IR) index. HOMA-IR is calculated by the following formula: HOMA-IR = fasting plasma glucose (mmol/L) × fasting insulin (uIU/mL)/22.5

- Glucose tests:

- Fasting plasma glucose: will be measured by Humastar 600 System (Humastar Systems,), sensitivity (S): 6.421 mmol/L and coefficient of variation (CV): 2.5% and performed when patients have already had fasting for at least 8 hours. A volume of 2 ml of blood will be withdrawn and contained in a vacutainer with additive of natri oxalate and EDTA. Diagnosis of diabetes mellitus will be made when fasting glucose ≥126 mg/dL (7 nmol/L) or HbA1C ≥6.5% (48 mmol/mol) (American Diabetes Association, 2018). When glucose ≥126 mg/dL (7 nmol/L) or HbA1C ≥6.5% (48 mmol/mol) (American Diabetes Association, 2018).

- Oral glucose tolerance test with 75 g glucose (75 g OGTT) will be performed to those with normal fasting glucose and HbA1C levels. Women will be recommended to have normal diet for 3 days and overnight fasting for at least 8 hours. The blood withdrawal will be performed twice: (i) fasting and (2i) 2 hours after solution administration. The volume of blood for each test is 2 ml. Impaired glucose tolerance will be diagnosed when two-hour glucose levels of 140 to 199 mg/dL (7.8 to 11.0 mmol/l) (American Diabetes Association, 2018).

- Hyperandrogenism:

- Clinical hyperandrogenism: Hirsutism using the modified Ferriman Gallwey score (mFG) and severe acnes

- Biochemical hyperandrogenism: free testosterone (normal range below 2,53nmol/ml), free testosterone index, SHBG