Time 0 minutes (induced hyperglycemia for gestational diabetes)

The induced hyperglycemia test in pregnant women must normally be done between the 24th and 28th week of pregnancy and at any time when there is a high risk (presence of multiple clinical factors). There are two approaches to the test. First, the pregnant woman can undergo a simple screening test that does not require fasting (1 h glucose level post 50 g), then a 2-hour OGTT can be administered only to those women who had results between 7.8 and 11.0 mmol/L on the simple test. The other approach is to use only the OGTT in all pregnant women. Interpretation values vary slightly depending on the approach.

In the 2-step approach, a diagnosis of gestational diabetes is made when one or more results is abnormal: greater than or equal to 5.3 millimoles per litre of glucose at zero time (≥ 5.3 mmol/L), ≥ 10.6 mmol/L after 1 hour and ≥ 9.0 mmol/L after 2 hours.

For the OGTT in a single step (1 hour post 50 g test not used), a diagnosis of gestational diabetes is made when one or more results is abnormal: ≥ 5.1 mmol/L at zero time, ≥ 10.0 mmol/L after 1 hour and ≥ 8.5 mmol/L after 2 hours.