It has been recommended that a 2-h 75-g OGTT be performed on all women at
24 to 28 weeks’ gestation not previously found to have overt diabetes or gestational diabetes mellitus (GDM)
during early testing in their current pregnancy.
The test should be done in the
morning after an overnight fast of 8 - 14 hours and after at least 3
days of unrestricted diet (>150 grams carbohydrates per day) and
unlimited physical activity. The subject should remain seated and
should not smoke throughout the test.
One or more of the values from a 75-g OGTT must be equaled or exceeded
for the diagnosis of GDM.
A fasting plasma glucose > 7.0 mmol/L (126 mg/dl) is diagnostic of overt
1. International Association of Diabetes and Pregnancy Study Groups
Diabetes Care. 2010 Mar;33(3):676-82.