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 overt 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: | |||
| • Fasting: 92 mg/dL (5.1 mmol/L) | |||
| • 1 h: 180 mg/dL (10.0 mmol/L) | |||
| • 2 h: 153 mg/dL (8.5 mmol/L) | |||
| 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 overt diabetes. | |||
| If the plasma glucose level measured 1 h after the load is ≥140 mg/dL* (7.8 mmol/L), 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 if at least two of the following four plasma glucose levels (measured fasting and 1 h, 2 h, 3 h after the OGTT) are met or exceeded: | |||
| Carpenter/Coustan (56) | or | NDDG (57) | |
| • Fasting | 95 mg/dL (5.3 mmol/L) | 105 mg/dL (5.8 mmol/L) | |
| • 1 h | 180 mg/dL (10.0 mmol/L) | 190 mg/dL (10.6 mmol/L) | |
| • 2 h | 155 mg/dL (8.6 mmol/L) | 165 mg/dL (9.2 mmol/L) | |
| • 3 h | 140 mg/dL (7.8 mmol/L) | 145 mg/dL (8.0 mmol/L) | |
| 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 overt 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: | |||
| • Fasting: 92 mg/dL (5.1 mmol/L) | |||
| • 1 h: 180 mg/dL (10.0 mmol/L) | |||
| • 2 h: 153 mg/dL (8.5 mmol/L) | |||
| 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 overt diabetes. | |||
| If the plasma glucose level measured 1 h after the load is ≥140 mg/dL* (7.8 mmol/L), 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 if at least two of the following four plasma glucose levels (measured fasting and 1 h, 2 h, 3 h after the OGTT) are met or exceeded: | |||
| Carpenter/Coustan (56) | or | NDDG (57) | |
| • Fasting | 95 mg/dL (5.3 mmol/L) | 105 mg/dL (5.8 mmol/L) | |
| • 1 h | 180 mg/dL (10.0 mmol/L) | 190 mg/dL (10.6 mmol/L) | |
| • 2 h | 155 mg/dL (8.6 mmol/L) | 165 mg/dL (9.2 mmol/L) | |
| • 3 h | 140 mg/dL (7.8 mmol/L) | 145 mg/dL (8.0 mmol/L) | |
NDDG, National Diabetes Data Group.
*The ACOG recommends a lower threshold of 135 mg/dL (7.5 mmol/L) in high-risk ethnic populations with higher prevalence of GDM; some experts also recommend 130 mg/dL (7.2 mmol/L).