In the HAPO (Hyperglycaemia and Adverse Pregnancy Outcomes) study, the 75g OGTT threshold for GDM diagnosis was established. According to IADPSG/WHO 2013, which of the following fasting plasma glucose values on OGTT would ALONE diagnose GDM at 24–28 weeks?

• A Fasting ≥5.6 mmol/L (≥100 mg/dL)
• B Fasting ≥5.1 mmol/L (≥92 mg/dL) ✓
• C Fasting ≥6.1 mmol/L (≥110 mg/dL)
• D Fasting ≥7.0 mmol/L (≥126 mg/dL)

Explanation

IADPSG (International Association of Diabetes and Pregnancy Study Groups) criteria, endorsed by WHO 2013, define GDM by 75g OGTT as: fasting ≥5.1 mmol/L (92 mg/dL), OR 1-hour ≥10.0 mmol/L (180 mg/dL), OR 2-hour ≥8.5 mmol/L (153 mg/dL) — any ONE threshold suffices. A fasting ≥7.0 mmol/L on OGTT constitutes overt diabetes in pregnancy (not GDM). These thresholds were derived from HAPO linear association data with adverse outcomes. The lower fasting threshold (5.1 vs 5.6 for pre-diabetes) is unique to pregnancy.

Reference: Williams Obstetrics, 26th ed.

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Written and medically reviewed by the StethoPrep medical team.