Assessment of the glucose tolerance test in unselected pregnancy using 75 g glucose load.

A 75 g oral glucose tolerance test (OGTT) was performed in 618 unselected pregnant Chinese women between 24 and 28 weeks gestation. The glucose response at fasting, 1, 2 and 3 h were studied. At 2 h the glucose level at 2-standard deviation and 4-standard deviation above the mean came very close to the criteria of abnormality suggested by the World Health Organization (WHO): 8.3 mmol/l vs. 8.0 mmol/l for impaired glucose tolerance and 10.8 mmol/l vs. 11.0 mmol/l for gestational diabetes mellitus. The area under the glucose response curve also correlates best with the glucose levels at 2 h during the OGTT (y = 2.1x + 4.6, r = 0.885). The 75-g OGTT interpreted with the WHO criteria seems appropriate for pregnant Chinese women. The 75-g test has the added advantages of reducing administration cost and discomfort of the patients.