Table 1—

Screening strategy for detecting GDM

GDM risk assessment: Should be ascertained at the first prenatal visit
  • Low risk: Blood glucose testing not routinely required if all of the following characteristics are present:

    • Member of an ethnic group with a low prevalence of GDM

    • No known diabetes in first-degree relatives

    • Age <25 years

    • Weight normal before pregnancy

    • Weight normal at birth

    • No history of abnormal glucose metabolism

    • No history of poor obstetric outcome

  • Average risk: Perform blood glucose testing at 24–28 weeks using either:

    • Two-step procedure: 50 g glucose challenge test (GCT) followed by a diagnostic oral glucose tolerance test in those meeting the threshold value in the GCT.

    • One-step procedure: Diagnostic oral glucose tolerance test performed on all subjects.

  • High-risk: Perform blood glucose testing as soon as feasible, using the procedures described above if one or more of these are present:

    • Severe obesity

    • Strong family history of type 2 diabetes

    • Previous history of: GDM, impaired glucose metabolism, or glucosuria

            If GDM is not diagnosed, blood glucose testing should be repeated at 24–28 weeks or at any time a patient has symptoms or signs that are suggestive of hyperglycemia.
  • Reproduced with minor modifications from Metzger et al. (9). “Weight normal at birth” is an additional low-risk criterion that must now be met.