Reference Range for Normal Glucose Tolerance

In daily life, pregnant women undergo routine prenatal examinations to monitor their baby’s healthy development in utero. Specific tests are scheduled at designated time points during pregnancy. What, then, is the reference range for normal glucose tolerance test (GTT) values?

Reference Range for Normal Glucose Tolerance Test Values

Normal GTT values are defined as follows: fasting plasma glucose < 5.1 mmol/L; 1-hour post-glucose load glucose < 10.0 mmol/L; and 2-hour post-glucose load glucose < 8.5 mmol/L. If any one of these three values exceeds its respective threshold, gestational diabetes mellitus (GDM) can be diagnosed. Specifically, GDM is diagnosed when any one of the following criteria is met: fasting plasma glucose ≥ 5.1 mmol/L; 1-hour post-glucose load glucose ≥ 10.0 mmol/L; or 2-hour post-glucose load glucose ≥ 8.5 mmol/L.

When blood glucose levels are elevated but do not meet the diagnostic criteria for overt diabetes, initial management should focus on lifestyle modifications. This includes controlling total caloric intake, eating smaller, more frequent meals, prioritizing high-fiber foods, and engaging in appropriate physical activity suitable for pregnancy—all aimed at achieving optimal glycemic control. If blood glucose remains poorly controlled despite lifestyle interventions, insulin therapy should be initiated promptly.

For pregnant women scheduled to undergo the GTT, maintain a normal diet for the three days preceding the test. On the evening before the test, fast after 9:00 p.m.—no food or drink (except water) should be consumed thereafter. We hope this information is helpful!