To date, The International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria for the diagnosis of gestational diabetes mellitus (GDM) have not been analyzed systematically for medical, social, and economic ramifications if used in substitution for the current GDM diagnostic criteria. The IADPSG dependence on expert opinion and consensus rather than on rigorously obtained outcome measures is concerning given the dramatic changes in clinical intervention and medical-resource reallocation that would follow their wide adoption. This commentary attempts to highlight needed research as well as the key knowledge gaps that should prevent adoption of the revised criteria until their effect on perinatal outcomes and health care costs is determined. In light of the overall, ethnic, and regional variation in GDM prevalence and the demands of increased GDM diagnosis on clinical resources, it may not be realistic and practical to impose universal strategies and standards for diagnosis. The newly proposed criteria may affect medical care negatively, unnecessarily stigmatize patients with a “sick label,” and adversely affect health care costs without ensuring the desired improvements in maternal and neonatal outcomes. This commentary serves as a caution to not promote a new endeavor until it has been compared rigorously with current practice and its implications are understood fully.