Evaluation of the WHO criteria for 75 g oral glucose tolerance test in pregnancy.

A group of pregnant women at high risk of developing diabetes in pregnancy had paired oral glucose tolerance tests (OGTT) using a 100 g load followed by 75 g load. When the World Health Organization (WHO) criteria and the National Diabetes Data Group (NDDG) criteria were compared, the 2-h plasma glucose value after the 100 g load was the most discriminative in differentiating those with normal glucose tolerance, impaired glucose tolerance and gestational diabetes mellitus. When only the 2-h plasma glucose values were assessed, the WHO test (75 g: 8 mmol/l) agreed with the NDDG test (100 g load: 9.2 mmol/l) in the diagnosis of glucose intolerance in 60% of subjects only. Using the same criteria at 2-h (8 mmol/l) the agreement between these tests was 47%. Reducing the glucose load from 100 g to 75 g produced a reduced glucose response in 49% of the subjects, with a significant decrease in the area under the glucose response curve.