Which test is used to screen for gestational diabetes during pregnancy?

• A. Oral glucose tolerance test
• B. Fasting glucose alone
• C. HbA1c alone
• D. Random glucose measurement

Answer: (A)

Gestational diabetes screening relies on checking how well the body handles a glucose load, not just a single fasting value. During pregnancy, placental hormones cause insulin resistance, so many individuals may pass fasting tests but still have elevated glucose after a meal or glucose challenge. The oral glucose tolerance test provides a controlled glucose challenge and measures glucose levels at specific intervals after ingestion, capturing the body's entire response. This dynamic assessment is more reliable for detecting impaired glucose tolerance in pregnancy than a fasting glucose alone, HbA1c alone (which can miss pregnancy-related changes in glucose patterns and isn’t as sensitive for GDM), or a random glucose measurement (which varies a lot and lacks standardized thresholds). For these reasons, the oral glucose tolerance test is the test of choice for screening gestational diabetes.