SHBG and gestational diabetes: The essential biomarkers for GDM detection are adipokines (leptin, tumor necrosis factor (TNF), interleukin 6 (IL-6), etc.), glycoproteins (afamin, CD59, sex-hormone binding protein (SHBG)), pregnancy-associated plasma protein-A (PAPP-A), C-reactive protein (CRP), and retinol-binding protein 4 (RBP4) (Figure 1) [44,45].