- GDM Group: GDM diagnosis will be based on International Association of the Diabetes in Pregnancy Study Group (IADPSG) and WHO, Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study (2 h 75 g oral glucose tolerance test (OGTT): a fasting glucose ≥ 92 mg/dl or a one hour result of ≥ 80 mg/dl, or a two hour result of ≥ 153 mg/dl;