Screening for and diagnosis of GDM
One-step strategy |
Perform a 75-g OGTT, with plasma glucose measurement when patient is fasting and at 1 and 2 h, at 24–28 weeks of gestation in women not previously diagnosed with diabetes. |
The OGTT should be performed in the morning after an overnight fast of at least 8 h. |
The diagnosis of GDM is made when any of the following plasma glucose values are met or exceeded:
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Two-step strategy |
Step 1: Perform a 50-g GLT (nonfasting), with plasma glucose measurement at 1 h, at 24–28 weeks of gestation in women not previously diagnosed with diabetes. |
If the plasma glucose level measured 1 h after the load is ≥130, 135, or 140 mg/dL (7.2, 7.5, or 7.8 mmol/L, respectively), proceed to a 100-g OGTT. |
Step 2: The 100-g OGTT should be performed when the patient is fasting. |
The diagnosis of GDM is made when at least two* of the following four plasma glucose levels (measured fasting and at 1, 2, and 3 h during OGTT) are met or exceeded (Carpenter-Coustan criteria [154]):
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GDM, gestational diabetes mellitus; GLT, glucose load test; OGTT, oral glucose tolerance test.
↵* American College of Obstetricians and Gynecologists notes that one elevated value can be used for diagnosis (150).