In accordance with the recommendations of the IADPSG in searching for “simpler and more cost-effective strategies that do not require performing an OGTT,” serum afamin concentrations may be a very suitable and easily applicable biomarker that can be used to diagnose patients for GDM during the second trimester of pregnancy or even to screen patients in high risk to develop GDM as early as possible during the first trimester. This evidence concerns the gene AFM and gestational diabetes.