What is the normal value for the glucose screening test?

To determine whether a pregnant woman has gestational diabetes mellitus (GDM). This screening is especially important for relatively obese pregnant women, those with a family history of diabetes, or those with prior adverse pregnancy outcomes—these individuals should undergo glucose screening proactively to confirm the diagnosis. So, what are the normal reference values for glucose screening?

What Are the Normal Reference Values for Glucose Screening?

The normal reference ranges for glucose screening are as follows: fasting plasma glucose < 5.1 mmol/L; 1-hour postprandial glucose < 10.0 mmol/L; and 2-hour postprandial glucose < 8.5 mmol/L. Glucose screening (commonly referred to as the oral glucose tolerance test, OGTT) is typically performed between 24 and 28 weeks of gestation and serves both as a screening tool and the gold standard for diagnosing GDM. During the OGTT, if any one of the following thresholds is met or exceeded—fasting plasma glucose ≥ 5.1 mmol/L, 1-hour plasma glucose ≥ 10.0 mmol/L, or 2-hour plasma glucose ≥ 8.5 mmol/L—the diagnosis of gestational diabetes mellitus is confirmed.

Screening for gestational diabetes is critically important because uncontrolled hyperglycemia during pregnancy poses significant risks to both the mother and the fetus. If elevated blood glucose remains undetected in the mother, it increases the risk of pregnancy-induced hypertension (PIH). For the fetus, maternal hyperglycemia may lead to abnormal amniotic fluid volume, impair the intrauterine growth environment, delay fetal lung maturation in late gestation, and cause abnormal fetal weight—resulting either in macrosomia or, conversely, in a term infant with low birth weight.

Therefore, glucose screening should be performed at the recommended gestational time point. If abnormalities are detected, management must be initiated under the guidance of a healthcare provider. We hope this information is helpful to you!