Updated ACOG Guidance on Gestational Diabetes

SUMMARY:

ACOG released updated guidance on gestational diabetes (GDM), which has become increasingly prevalent worldwide.  Class A1GDM refers to diet-controlled GDM. Class A2GDM refers to the clinical scenario where medications are required. Highlights and changes from the previous practice bulletin include the following:

Screening for GDM – One or Two Step?

  • ACOG (based on NIH consensus panel findings) supports the ‘2 step’ approach (24 – 28 week 1 hour venous glucose measurement following 50g oral glucose solution), followed by a 100g 3 hour oral glucose tolerance test (OGTT) if positive
    • Note: Diagnosis of GDM is based on 2 abnormal values on the 3 hour OGTT
      • ACOG recommends that currently there is insufficient evidence to diagnose GDM based on only one abnormal value
      • Patients with only one elevated value may require additional surveillance
  • 1 step approach (75 g OGTT) on all women will increase the diagnosis of GDM but sufficient prospective studies demonstrating improved outcomes still lacking
  • ACOG does acknowledge that some centers may opt for ‘1 step’ if warranted based on their population
  • ADA considers either 1 step or 2 step (using Coustan Carpenter criteria) to both be valid for GDM diagnosis
  • The USPSTF
    • Recommends screening for gestational diabetes in asymptomatic pregnant persons at ≥24 weeks of gestation or after (B recommendation)
    • Current evidence is insufficient to assess the balance of benefits and harms of screening for gestational diabetes in asymptomatic pregnant persons <24 weeks of gestation (I statement)

Who Should be Screened Early?

ACOG has adopted the NIDDK / ADA guidance on screening for diabetes and prediabetes which takes in to account not only previous pregnancy history but also risk factors associated with type 2 diabetes. Consider early screening in pregnancy if:

Patient is overweight with BMI of 25 (23 in Asian Americans), and one of the following

  • Physical inactivity
  • Known impaired glucose metabolism
  • Previous pregnancy history of:
    • GDM
    • Macrosomia (≥ 4000 g)
    • Stillbirth
  • Hypertension (140/90 mm Hg or being treated for hypertension)
  • HDL cholesterol ≤ 35 mg/dl (0.90 mmol/L)
  • Fasting triglyceride ≥ 250 mg/dL (2.82 mmol/L)
  • PCOS,  acanthosis nigricans, nonalcoholic steatohepatitis, morbid obesity and other conditions associated with insulin resistance
  • Hgb A1C ≥ 5.7%, impaired glucose tolerance or impaired fasting glucose | If A1C>6.5%, diagnosis of pregestational diabetes is met and GCT/GTT not needed
  • Cardiovascular disease
  • Family history of diabetes – 1st degree relative (parent or sibling)
  • Ethnicity of African American, American Indian, Asian American, Hispanic, Latina, or Pacific Islander

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