BC ADM Gestational & Pregestational Diabetes Management

Question 1

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

Accepted Answer

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

Answer

75g OGTT with a single fasting value threshold

Answer

Fasting glucose at first prenatal visit followed by HbA1c at 24 weeks

Answer

Direct 3-hour 100g OGTT without prior screening

Question 2

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

Accepted Answer

2 or more values meeting threshold

Answer

1 or more values meeting threshold

Answer

3 or more values meeting threshold

Answer

All 4 values must meet threshold

Question 3

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

Accepted Answer

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

Answer

Fasting ≥100, 1-hr ≥190, or 2-hr ≥160 mg/dL (any two values)

Answer

Fasting ≥95, 1-hr ≥180, and 2-hr ≥155 mg/dL (all three values)

Answer

Fasting ≥126 or 2-hr ≥200 mg/dL

Question 4

What is the primary pathophysiologic mechanism underlying gestational diabetes mellitus?

Accepted Answer

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

Answer

Autoimmune destruction of pancreatic beta cells triggered by pregnancy hormones

Answer

Excess glucagon secretion from maternal alpha cells during the second trimester

Answer

Decreased hepatic glucose production due to fetal glucose uptake

Question 5

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

Accepted Answer

Nulliparity (no prior pregnancies)

Answer

Pre-pregnancy BMI greater than 25 kg/m²

Answer

Previous delivery of a macrosomic infant (>9 lbs)

Answer

First-degree relative with type 2 diabetes

Question 6

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

Accepted Answer

At the first prenatal visit using standard adult diabetes diagnostic criteria

Answer

At 24-28 weeks using the standard GDM two-step protocol

Answer

At 16-20 weeks with a 75g OGTT regardless of risk factors

Answer

Only if HbA1c exceeds 6.0% at any prenatal visit

Question 7

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?

Accepted Answer

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

Answer

Diagnose GDM and initiate lifestyle modifications immediately

Answer

Repeat the 3-hour OGTT in 4 weeks

Answer

Initiate insulin therapy given the high GCT value