Table 18-3. Screening and diagnostic criteria for gestational diabetes mellitus

Screening for gestational diabetes mellitus

1. 50-g oral glucose load, administered between the 24th and 28th weeks, without regard to time of day or time of last meal. Universal blood glucose screening is indicated for patients who are of Hispanic, African, Native American, South or East Asian, Pacific Island, or Indigenous Australian ancestry. Other patients who have no known diabetes in first-degree relatives, are under 25 years of age, have normal weight before pregnancy, and have no history of abnormal glucose metabolism or poor obstetric outcome do not require routine screening.


2. Venous plasma glucose measure 1 hour later.


3. Value of 130 mg/dL (7.2 mmol/L) or above in venous plasma indicates the need for a full diagnostic glucose tolerance test.


Diagnosis of gestational diabetes mellitus

1. 100-g oral glucose load, administered in the morning after overnight fast lasting at least 8 hours but not more than 14 hours, and following at least 3 days of unrestricted diet (< 150 g carbohydrate) and physical activity.


2. Venous plasma glucose is measured fasting and at 1, 2, and 3 hours. Subject should remain seated and should not smoke throughout the test.


3. Two or more of the following venous plasma concentrations must be equaled or exceeded for a diagnosis of gestational diabetes: fasting, 95 mg/dL (5.3 mmol/L); 1 hour, 180 mg/dL (10 mmol/L); 2 hours, 155 mg/dL (8.6 mmol/L); 3 hours, 140 mg/dL (7.8 mmol/L).