A 28-year-old primigravida from Delhi presents at 24 weeks gestation for routine antenatal care. She is asymptomatic with a BMI of 26 kg/m². Her fasting blood glucose is 95 mg/dL and 2-hour post-75 g oral glucose tolerance test (OGTT) value is 168 mg/dL. Her HbA1c is 5.8%. What is the most appropriate next step in management?

Explanation

## Diagnosis of Gestational Diabetes **Key Point:** This patient meets diagnostic criteria for gestational diabetes mellitus (GDM) based on the 75 g OGTT performed at 24 weeks. ### OGTT Diagnostic Criteria (WHO/IADPSG) The 75 g OGTT is performed at 24–28 weeks gestation. A single abnormal value is diagnostic of GDM: | Time Point | Diagnostic Threshold (mg/dL) | |---|---| | Fasting | ≥92 | | 1 hour | ≥180 | | 2 hour | ≥153 | **Clinical Pearl:** In this patient, the 2-hour value of 168 mg/dL exceeds the threshold of 153 mg/dL, confirming GDM diagnosis. A single abnormal value is sufficient — no need to repeat. ### Immediate Management of Confirmed GDM 1. **Medical Nutrition Therapy (MNT)** — first-line intervention - Individualized dietary counseling by dietitian - Carbohydrate counting, portion control, emphasis on complex carbs - Modest caloric restriction if overweight (not weight loss) 2. **Self-Monitoring of Blood Glucose (SMBG)** - Fasting and postprandial (2 hours after meals) glucose targets: - Fasting: <95 mg/dL - Postprandial: <120 mg/dL (some guidelines: <140 mg/dL) - Frequency: 4 times daily (fasting + 3 postprandial) 3. **Pharmacotherapy** — indicated if MNT fails to achieve targets after 1–2 weeks - First-line: Insulin (safest in pregnancy) - Second-line: Metformin (if patient declines insulin and has no contraindications) **High-Yield:** The diagnosis is already established; the next step is initiation of MNT and glucose monitoring, NOT further testing or reassurance. ### Why Other Options Are Incorrect - **Repeat OGTT in 4 weeks:** Unnecessary; one abnormal value confirms diagnosis. Repeating delays treatment initiation. - **Start metformin without MNT:** Metformin is second-line; MNT is mandatory first-line. Insulin is preferred in pregnancy. - **Reassure patient:** Dangerous; untreated GDM increases risk of preeclampsia, fetal macrosomia, shoulder dystocia, and neonatal hypoglycemia. **Mnemonic:** GDM Management = **MNT First, Then Insulin** (MFTI) — Medical Nutrition Therapy is always the foundation; pharmacotherapy added only if targets not met.