CCL2 and Insulin resistance: Therefore, in this study, through systematic analyses of selected inflammatory cytokines and GDM in both the second and third trimesters, we aimed to explore the differences in serum levels of nerve growth factor (NGF), IL-6, leptin, IL-8, monocyte chemoattractant protein-1 (MCP-1), Interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) between GDM patients and normal controls, and to analyse the exact correlations of these cytokines with glucose metabolism, insulin resistance and pancreatic β cell function.