Geographic, ethnic, and racial variations in the incidence of gestational diabetes mellitus.

The prevalence of diabetes and of gestational diabetes varies considerably between countries and within countries. There are also major national and international differences in the important end points of fetal or neonatal death and congenital fetal abnormality. These differences relate to multiple factors, of which diabetes or gestational diabetes represents only a part of the total pathologic effect. There is also international disagreement on the most appropriate diagnostic criteria for gestational diabetes. The main uncertainty is whether to adopt the World Health Organization figures, e.g., venous plasma glucose 2 h after 75 g glucose greater than or equal to 140 mg/dl (8.0 mmol/L) as gestational impaired glucose tolerance, and greater than or equal to 200 mg/dl (11.0 mmol/L) as gestational diabetes, or to use the Boston figures, e.g., venous plasma glucose 2 h after 100 g glucose greater than or equal to 165 mg/dl (9.5 mmol/L) as gestational diabetes. It is hoped that standards for pathologic hyperglycemia in pregnancy can be agreed on for use in all countries for all populations.