HAPO was a multicenter international study that included more than 23,000 women in nine countries who were given a 75-gram, two-hour OGTT. Results clearly demonstrated strong and continuous associations between maternal glucose and adverse outcomes such as increased birth weight, C-section delivery, and neonatal hypoglycemia. The continuous associations between glucose and outcome meant that translating the HAPO results into clinical practice would be challenging. Recognizing that, the study investigators called for a re-defi ning of the criteria used to diagnose GDM. As a result, the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) convened to establish new diagnostic criteria for the diagnosis of GDM.