The two-step approach for diagnosing GDM is preferred over the single-step approach….
The current two-step approach for diagnosing gestational diabetes mellitus (GDM) includes a 50 gram glucose challenge and a 100 gram glucose challenge. If the patient’s blood glucose 1 hour after the 50 gram glucose challenge is less than a selected cutoff (130, 135, of 140 mg/dL), the patient does not have gestational diabetes. If not, the second glucose challenge of 100 gram glucose is needed. However, the World Health Organization (WHO) and the International Association of Diabetes and Pregnancy Study Group (IADPSG) prefer the single-step approach which involves a single 75 gram glucose challenge, 2-hour OGTT. In response to that, an independent panel from the National Institute of Health stated that a two-step approach for diagnosing gestational diabetes is still preferred.
"The panel believes that there is not presently sufficient evidence to adopt a one-step approach. We are particularly concerned that the adoption of new criteria would increase the prevalence and corresponding costs of [gestational diabetes] without clear demonstration of improvements in key short- and long-term outcomes," said Dr. Peter VanDorsten, the panel chairman and the Lawrence L. Hester Jr. Professor in the division of maternal-fetal medicine at the Medical University of South Carolina.