SHBG and Obesity: Recently, a number of biomarkers have been identified for early detection of GDM, such as sex hormone binding globulin (SHBG) [28] and placental growth hormone (PGH) [29], which are related to pregnancy, as well as free fatty acids [30], adiponectin [31, 32], and follistatin-like-3 [33] which correlate with obesity and lipid metabolism.