Lin J, et al. - This case-control study was undertaken to determine if insulin resistance (IR) in the second trimester is correlated with certain specific adverse pregnancy outcomes, as well as to further investigate the risk factors for IR in the second trimester in Chinese GDM women. A retrospective survey of 710 women with GDM was used in this study. In the first trimester (6–12 weeks), serum lipids, fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), and serum protein were measured, while the OGTT and fasting insulin tests were conducted in the second trimester (24–28 weeks). GDM combined with IR in the second trimester increased the risk of adverse pregnancy outcomes, particularly hypertensive disorders of pregnancy and large for gestational age. Furthermore, FPG, HbA1c, and TG in early pregnancy, pre-pregnancy BMI, and weight gain prior to GDM diagnosis were all independent risk factors for IR.