A comparative evaluation of the 75 G OGTT and the 50 G OGTT during pregnancy

The aim of the present study was to establish reference values for the diagnosis gestational diabetes (GD) by the 75 g OGTT using the 3 hr 50 g OGTT as a reference. Women with an area of greater than or equal to 42 AU in the 50 g OGTT were regarded as gestational diabetics. Sixty-one women with a 3 hr area of greater than or equal to 39 AU in the 50 g OGTT were subject also to a 3 hr 75 g OGTT within one week. 25/61 had GD according to the result of the 50 g OGTT. The 2 hr concentration in the 75 g OGTT had the highest correlation (r = 0.62, p less than 0.001) to the 3 hr-area in the 50 g OGTT. A 2 hr B-glucose concentration of greater than or equal to 8.0 mmol/l in the 75 g OGTT will give about the same number of GD patients (25/61) as a 3 hr-area of greater than or equal to 42 in the 50 g OGTT and have an acceptable sensitivity without too low specificity.