Early Gestational Diabetes Screening Falls Short

Marlene Busko, for Medscape

February 07, 2022

The study covered in this summary was published in Preprints With The Lancet and has not yet been peer reviewed.

Key Takeaways

  • Oral glucose tolerance tests (OGTTs) for gestational diabetes mellitus (GDM) given early in pregnancy, during gestational weeks 12-15, using the 2013 diagnostic criteria of the World Health Organization (WHO) were not as sensitive nor accurate for diagnosis as when the same diagnostic criteria were applied during the current standard assessment window of 24-28 weeks gestation.

Why This Matters

  • This is the first study to prospectively assess the WHO 2013 GDM diagnostic criteria for screening low-risk women at gestational weeks 12-15, and the results address the diagnostic accuracy of using the WHO 2013 criteria for an OGTT during this early phase of pregnancy.

  • Diagnosis of early onset GDM is important because it results in worse maternal and neonatal outcomes and effective treatment is challenging.

Study Design

  • The Predictability of Gestational Diabetes Mellitus in First and Second Trimester (GDMPredict) trial prospectively enrolled 636 women age 18-45 with a singleton pregnancy at low risk of GDM seen at any of six participating sites in Austria, Germany, and Switzerland between March 2015 and January 2019.

  • All women had an early 75-g OGTT at gestational week 12-15 and a late 75-g OGTT at gestational week 24-28.

  • Clinicians applied the WHO 2013 diagnostic criteria for GDM based on women meeting at least one of three criteria for plasma glucose levels before or following a 75-g OGTT:

    • Fasting glucose ≥ 5.1 mmol/L (≥ 92 mg/dL)

    • 1-hour post-challenge glucose ≥ 10.0 mmol/l (≥ 180 mg/dL)

    • 2-hour post-challenge glucose ≥ 8.5 mmol/L (≥ 153 mg/dL)

Key Results

  • Seventy-four (12%) of the women had GDM based on an OGTT at gestational week 24-28, indicating the study cohort had a low risk of developing GDM.

  • The early OGTT had:

    • High specificity with a true negative result rate of 96% and a high negative predictive value of 92%.

    • Low sensitivity of 35% and a low positive predictive value of 57%.

    • Overall accuracy was high, at 89%.

Limitations

  • The study did not consider possible changes in the women's characteristics and comorbidities from the time of the early versus late OGTTs, and hence, cannot describe a phenotype characteristic of early onset GDM.

  • The study population was mainly White, so the findings cannot be generalized to more diverse populations.

Disclosures

  • The study received no commercial funding.

  • None of the authors had disclosures.

This is a summary of a preprint research study, "WHO 2013 criteria for diagnosis of gestational diabetes mellitus in low-risk women in early pregnancy: an international prospective cohort study" written by researchers from universities in Austria, Germany, and Switzerland. Preprints with The Lancet are provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found here.

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