Gestational diabetes mellitus.
Detection and Diagnosis
Risk assessment for gestational diabetes mellitus should be undertaken at the first prenatal visit. Women with clinical characteristics consistent with a high risk of gestational diabetes mellitus (marked obesity, personal history of gestational diabetes mellitus, glycosuria, or a strong family history of diabetes) should undergo glucose testing (see below) as soon as feasible. If they are found not to have gestational diabetes mellitus at that initial screening, they should be retested between 24 and 28 weeks of gestation. Women of average risk should have testing undertaken at 24 to 28 weeks of gestation. Low-risk status requires no glucose testing, but this category is limited to those women meeting all of the following characteristics:
A fasting plasma glucose level >126 mg/dL (7.0 mmol/L) or a casual plasma glucose >200 mg/dL (11.1 mmol/L) meets the threshold for the diagnosis of diabetes, if confirmed on a subsequent day, and precludes the need for any glucose challenge. In the absence of this degree of hyperglycemia, evaluation for gestational diabetes mellitus in women with average or high-risk characteristics should follow one of two approaches:
One-step approach: Perform a diagnostic oral glucose tolerance test (OGTT) without prior plasma or serum glucose screening. The one-step approach may be cost-effective in high-risk patients or populations (e.g., some Native-American groups).
Two-step approach: Perform an initial screening by measuring the plasma or serum glucose concentration 1 hour after a 50-g oral glucose load (glucose challenge test [GCT]) and perform a diagnostic oral glucose tolerance test on that subset of women exceeding the glucose threshold value on the glucose challenge test. When the two-step approach is employed, a glucose threshold value >140 mg/dL (7.8 mmol/L) identifies approximately 80% of women with gestational diabetes mellitus, and the yield is further increased to 90% by using a cutoff of >130 mg/dL (7.2 mmol/L).
With either approach, the diagnosis of gestational diabetes mellitus is based on an oral glucose tolerance test. Diagnostic criteria for the 100-g oral glucose tolerance test are shown in Table 1, below. Alternatively, the diagnosis can be made using a 75-g glucose load and the glucose threshold values listed for fasting, 1 hour, and 2 hours (Table 2, below); however, this test is not as well validated for detection of at-risk infants or mothers as the 100-g oral glucose tolerance test.
Table 1. Diagnosis of gestational diabetes mellitus with a 100-g oral glucose load
Two or more of the venous plasma concentrations must be met or exceeded for a positive diagnosis. The test should be done in the morning after an overnight fast of between 8 and 14 h and after at least 3 days of unrestricted diet (>150 g carbohydrate per day) and unlimited physical activity. The subject should remain seated and should not smoke throughout the test.
Table 2. Diagnosis of gestational diabetes mellitus with a 75-g oral glucose load
Information on obstetric and perinatal considerations can be found in the original guideline document.
Monitoring
Management
Fasting plasma glucose <105 mg/dL (5.8 mmol/L)
or
1-hour postprandial plasma glucose <155 mg/dL (8.6 mmol/L)
2-hour postprandial plasma glucose <130 mg/dL (7.2 mmol/L)
Long-term Therapeutic Considerations
None provided
References open in a new window
The recommendations are based on the evidence reviewed in the following publications: Report of the expert committee on the diagnosis and classification of diabetes mellitus. Diabetes Care 1998;21(Suppl 1):S5-S19; and the Proceedings of the 4th International Workshop-Conference on Gestational Diabetes Mellitus. Diabetes Care 1998;21(Suppl 2):B1-B167.
Not applicable: The guideline was not adapted from another source.
1986 (revised 2000; republished 2004 Jan)
American Diabetes Association - Professional Association
The American Diabetes Association (ADA) received an unrestricted educational grant from LifeScan, Inc., a Johnson and Johnson Company, to support publication of the 2004 Diabetes Care Supplement.
Professional Practice Committee
Not stated
This is the current release of the guideline.
This guideline was originally approved in 1986. The most recent review/revision was completed in 2000.
American Diabetes Association (ADA) position statements are reissued annually.
Electronic copies: Available from the American Diabetes Association (ADA) Web site.
Print copies: Available from American Diabetes Association, 1701 North Beauregard Street, Alexandria, VA 22311.
The following is available:
Print copies: Available from the American Diabetes Association (ADA), 1600 Duke Street, Alexandria, VA 22314.
None available
This summary was completed by ECRI on April 2, 2001. The information was verified by the guideline developer on August 24, 2001. The summary was updated by ECRI on January 29, 2002, April 21, 2003, and March 24, 2004.
This NGC summary is based on the original guideline, which is copyrighted by the American Diabetes Association (ADA).
For information on guideline reproduction, please contact Alison Favors, Manager, Rights and Permissions by e-mail at permissions@diabetes.org.
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