A number of challenges remain for screening and diagnostic testing for GDM. All of the diagnostic criteria for pregnancy in common use in the United States are based on the 100-g, 3-hour Oral Glucose Tolerance Test (OGTT). There are a number of reasons, however, that a 75-g test would be preferable. First, when a glucose tolerance test is administered to nonpregnant individuals, it is standard to use the 75-g, 2-hour OGTT. Using a different glucose challenge in pregnant verses nonpregnant patients leads to confusion in the laboratory and may result in errors in applying the proper diagnostic criteria. Further, the 75-g, 2-hour OGTT is in use during pregnancy in many countries around the world, typically using the same thresholds as in nonpregnant individuals. Development and validation of pregnancy-based criteria using the 75-g, 2-hour OGTT would simplify world wide comparison of data and the testing paradigm used in the United States.
Coustan, Donald R. MD, â€œMaking the diagnosis of Gestational Diabetes Mellitus (Diabetes and Pregnancy)â€ Clin Obstet Gynecol. 2000 Mar;43(1):99-105.