Objective: The purpose of this study attempts to determine the endocrinologic characteristics and changes in glucose metabolism before/during pregnancy according to different body weights in women with Polycystic ovarian syndrome (PCOS). Methods: 94 women dia with PCOS were evaluated through measuring serum hormone levels and oral glucose tolerance tests preconceptionally and gestationally. Results: In patients who were of normal weight showed significantly increased serum LH levels compared to those who were overweight (12.8+-0.9 Vs. 7.1+-0.8 mIU/ml, p= 0.000), and the serum levels of insulin was increased significantly in the overweight group (7.1+-0.7 Vs. 15.2+-2.8 ulU/ml, p= 0.000). the IGFBP-I (32.8+-10.6 Vs. 8.3+-2.5 ng/ml, p=0.034) and SHBG (55.8+-4.2 Vs. 37.1+-3.1 nmol/ml, p= 0.001) were significantly lower in the ovnweight group. The oral glucose tolerance test before/after pregnancy showed increased frequency of abnormal glucose metabolism, in both of the non-obese group (38.8%, 26,9%) and the obese group (64.2%, 53.9%) compared with normal population. Conclusion: It is thought that in the normal weight group with polycystic ovarian syndrome androgen production is stimulated in the theca cells by abnormally high LH secretion, while in the overweight group the hyperinsulinemia state which decreases the SHBG and IGFBP-I, lead to increase biologically active hee androgens and IGF-I and increase insulin binding to its receptor. And during/before pregnancy, women with PCOS showed that incidence of abnormal glucose metabolism was significantly increased in both of non-obese and obese groups.