Effects of Pioglitazone Combined With Metformin on Gonadal and Metabolic Profiles in Chinese Nonobese PCOS Patients.

Inclusion Criteria: 1. Females 18 years to 40 years of age Diagnosed as PCOS by the 2003 Rotterdam criteria 2. BMI\<24 kg/m2 3. No pregnant plan in recent 6 months 4. Written consent for participation in the study Exclusion Criteria: 1. type 1 or type 2 diabetes mellitus 2. Subjects have other endocrine diseases, such as adrenal hyperplasias or tumor, androgen-secreting tumors, Cushing's syndrome, thyroid diseases, and hyperprolactinemia 3. Diagnosed with or have a family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) 4. Serious systemic disease or malignant tumor 5. History of pancreatitis (chronic, acute or recurrent) 6. Body weight change ≥10% at 3 months before treatment 7. Used oral contraceptives or sex hormone drugs in the past 1 month 8. Used oral glucocorticoids in the past 1 month 9. Substance (alcohol or drug) abuse or dependence within 3 months 10. Heavy smokers (smokers who smoke 20 or more cigarettes a day) or heavy drinkers (\>10g/d) 11. Subjects have a severe systemic disease, such as cardiovascular system, Renal impairment (eGFR\<60ml/min/1.73m2) 12. Increase of transaminases up to \< 2.5 times of upper limit of normal value 13. Have a history of thromboembolic disease or thrombotic tendency 14. Subjects in pregnant or lactating or within 1 year after delivery 15. Subjects have an allergic history to the drugs used in the study 16. Subjects have participated in other clinical researches of medicine within 1 month prior to randomization 17. Use of metformin, pioglitazone, or pioglitazone combined with metformin within 30 days before screening