Gestational & Pregestational Diabetes Management Flashcards

What is the recommended two-step screening approach for gestational diabetes mellitus (GDM) at 24-28 weeks?

Answer: 50g glucose challenge test; if ≥140 mg/dL, proceed to 3-hour 100g OGTT

The two-step approach uses a non-fasting 50g GCT at 24-28 weeks; a 1-hour result ≥140 mg/dL triggers the diagnostic 3-hour 100g OGTT.

Using Carpenter-Coustan criteria for the 3-hour 100g OGTT, how many abnormal values are required to diagnose GDM?

Answer: 2 or more values meeting threshold

GDM is diagnosed when 2 or more of the 4 timed values (fasting, 1-hr, 2-hr, 3-hr) meet or exceed the Carpenter-Coustan thresholds.

Which glucose thresholds define GDM diagnosis using the one-step 75g OGTT (IADPSG/ADA criteria)?

Answer: Fasting ≥92, 1-hr ≥180, or 2-hr ≥153 mg/dL (any one value)

The IADPSG one-step 75g OGTT diagnoses GDM when any single value meets or exceeds fasting ≥92, 1-hr ≥180, or 2-hr ≥153 mg/dL.

What is the primary pathophysiologic mechanism underlying gestational diabetes mellitus?

Answer: Insulin resistance amplified by placental hormones combined with inadequate beta-cell compensation

GDM results from physiologic pregnancy-related insulin resistance—amplified by placental hormones such as human placental lactogen—combined with insufficient compensatory beta-cell insulin secretion.

Which of the following is NOT a recognized risk factor for gestational diabetes mellitus?

Answer: Nulliparity (no prior pregnancies)

Nulliparity is not a recognized risk factor for GDM; major risk factors include obesity, prior macrosomic infant, family history of T2DM, prior GDM, and certain ethnic backgrounds.

When should screening for undiagnosed pregestational diabetes occur in pregnant women with risk factors?

Answer: At the first prenatal visit using standard adult diabetes diagnostic criteria

Women with risk factors for undiagnosed type 2 diabetes should be screened at the first prenatal visit using standard non-pregnancy diagnostic thresholds (HbA1c, fasting glucose, or 75g OGTT).

A pregnant woman at 26 weeks has a 1-hour 50g GCT result of 158 mg/dL and subsequently a 3-hour 100g OGTT with only one value above the Carpenter-Coustan threshold. What is the appropriate clinical action?

Answer: Consider an individualized approach; one abnormal value may indicate impaired glucose tolerance warranting close follow-up

One abnormal OGTT value does not meet Carpenter-Coustan criteria for GDM but indicates impaired glucose tolerance; clinical guidelines support individualized dietary counseling and close monitoring in this scenario.