Gestational diabetes is a recognized risk factor for adverse outcomes during pregnancy and
has led to the routine screening of all pregnant patients. However, the initial threshold
criteria for its diagnosis were somewhat arbitrarily set at values> 2 SD above the mean for
the original study population, obtained over 40 years ago. More recently, accumulating
evidence indicates that lesser degrees of carbohydrate intolerance may increase risks for
perinatal complications.

Criteria for the diagnosis of gestational diabetes mellitus (GDM) 5 based on association of
levels of glycemia during pregnancy with subsequent maternal diabetes were first published
55 years ago (1). With adjustments for measurement of glucose in plasma rather than in
whole blood and use of enzymatic methods, these criteria remain in use in the US and some
other areas. Despite recognition of GDM by various professional organizations in 1979 to
1980, questions remained:(a) Were adverse outcomes attributed to GDM linked to maternal�…