Diagnosis of GDM by an oral glucose tolerance test
| . | Oral glucose load* . | . | . | . | |||
|---|---|---|---|---|---|---|---|
| . | 100-g glucose† . | . | 75-g glucose† . | . | |||
| Fasting‡ | 95 mg/dl | 5.3 mmol/l | 95 mg/dl | 5.3 mmol/l | |||
| 1-h‡ | 180 mg/dl | 10.0 mmol/l | 180 mg/dl | 10.0 mmol/l | |||
| 2-h‡ | 155 mg/dl | 8.6 mmol/l | 155 mg/dl | 8.6 mmol/l | |||
| 3-h‡ | 140 mg/dl | 7.8 mmol/l | — | — | |||
| . | Oral glucose load* . | . | . | . | |||
|---|---|---|---|---|---|---|---|
| . | 100-g glucose† . | . | 75-g glucose† . | . | |||
| Fasting‡ | 95 mg/dl | 5.3 mmol/l | 95 mg/dl | 5.3 mmol/l | |||
| 1-h‡ | 180 mg/dl | 10.0 mmol/l | 180 mg/dl | 10.0 mmol/l | |||
| 2-h‡ | 155 mg/dl | 8.6 mmol/l | 155 mg/dl | 8.6 mmol/l | |||
| 3-h‡ | 140 mg/dl | 7.8 mmol/l | — | — | |||
Data are from Metzger et al. (9).
The test should be performed in the morning after an overnight fast of at least 8 h but not more than 14 h and after at least 3 days of unrestricted diet (≥150 g carbohydrate/day) and physical activity. The subject should remain seated and should not smoke throughout the test.
Two or more of the venous plasma glucose concentrations indicated below must be met or exceeded for a positive diagnosis.
The cutoff values are those proposed by Carpenter and Coustan (10) for extrapolation of the whole blood glucose values found by O'Sullivan and Mahan (11) to plasma glucose concentrations.