Fasting plasma glucose to avoid a full OGTT in the diagnosis of gestational diabetes

AimsTo evaluate the performance of fasting plasma glucose (FPG) in determining the need for a full oral glucose tolerance test (OGTT) to diagnose gestational diabetes (GDM) by the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria.MethodsA multicenter cohort study of 4926 pregnant women 20 years or older consecutively enrolled in prenatal care clinics of the Brazilian National Health Service from 1991 to 1995. All women underwent a single 2 h 75 g OGTT by weeks 24-28 of pregnancy and were followed to detect adverse pregnancy outcomes.ResultsA FPG cut-off value of 80 mg/dl indicated that only 38.7% of all women needed to undergo a complete OGTT, while detecting 96.9% of all GDM cases. When the 85 mg/dl cut-off was used, the corresponding percentages were 18.7% and 92.5%, respectively. The fraction of women labeled with GDM who had adverse pregnancy outcomes was nearly identical when using FPG strategies and universal full testing.ConclusionsUsing a FPG cut-off to diagnose GDM and to determine the need for post-load OGTT measurements is a valid strategy to diagnose GDM by IADPSG criteria. This approach may improve feasibility of applying IADPSG diagnostic criteria by reducing costs and increasing convenience.