Nowadays, Gestational diabetes mellitus - GDM is paid attention because of many risks for pregnant women and unborn babies. Over the last years, some prestigious organizations in the world as ADA (American Diabetes Association), IDF (International Diabetes Federation), WHO (World Health Organization), IADPSG (International Association of Diabetes and Pregnancy Study Groups)... have published some guidelines concern with gestational diabetes mellitus. These guidelines all agree in some issues, but not agree in some as: Diagnostic criteria, classification, time to screen of gestational diabetes mellitus...