A fasting blood glucose screening in pregnancy shows 140 mg/dL. Which measure is most likely prescribed next?

• A. An oral hypoglycemic agent
• B. A 3-hour glucose tolerance test
• C. Humulin N insulin on a daily basis
• D. A sliding-scale regular insulin dose

Answer: (B)

When screening in pregnancy suggests elevated glucose, the next step is to confirm whether gestational diabetes is present with a diagnostic test. A 3-hour glucose tolerance test using a 100 g glucose load after an overnight fast provides multiple time-point measurements (fasting, 1 hour, 2 hours, and 3 hours). The diagnosis is made if enough of these values are above the established thresholds (often two or more abnormal results, depending on the criteria used).

This single fasting value by itself isn’t enough to diagnose gestational diabetes, so starting medications isn’t indicated yet. The options that involve giving glucose-lowering drugs—whether an oral agent or insulin—are treatments for confirmed diabetes, not steps to confirm it. Sliding-scale insulin isn’t appropriate here either without a confirmed diagnosis.

So the best next step is the 3-hour glucose tolerance test to establish whether gestational diabetes is present.