Understanding Gestational Diabetes (GDM)
Gestational diabetes refers to high blood sugar first diagnosed during pregnancy, affecting 5-15% of pregnancies. It occurs when placental hormones disrupt insulin function, leading to insulin resistance.
3 Types of Pregnancy-Related Diabetes
- Pre-existing diabetes (Type 1/2 diagnosed before pregnancy)
- Gestational diabetes (GDM) – Diagnosed at 24–28 weeks via glucose testing
- Newly diagnosed diabetes in early pregnancy
Risks to Mother & Baby
For Baby
- Macrosomia (oversized baby) → Birth trauma, shoulder dystocia
- Neonatal hypoglycemia, jaundice
- ↑ Future risk of childhood obesity & type 2 diabetes
For Mother
- ↑ C-section rates, preeclampsia
- 50% risk of developing type 2 diabetes within 10 years
Diagnosis: 1-Step vs. 2-Step Testing
2-Step Method (Traditional)
- 50g OGTT (non-fasting):
- 1-hour glucose **≥140 mg/dL** → Proceed to step 2
- 100g OGTT (fasting):
- 2+ abnormal values = GDM
- Cutoffs: Fasting ≥95, 1h ≥180, 2h ≥155, 3h ≥140
1-Step Method (Preferred)
- 75g OGTT (fasting):
- 1+ abnormal values = GDM
- Cutoffs: Fasting ≥92, 1h ≥180, 2h ≥153
Note: The 1-step method better predicts pregnancy complications.
Managing GDM: 4 Key Strategies
1. Blood Sugar Monitoring
- Test 4x/day: Fasting + 1h/2h post-meals
- Targets:
- Fasting: <95 mg/dL
- 1h post-meal: <140 mg/dL
- 2h post-meal: <120 mg/dL
- Good news: Taiwan NHI now covers 5 test strips/day until delivery!
2. Diet Adjustments
- Carb control: 30–45g/meal (avoid refined carbs)
- Protein + fiber: Slow glucose absorption
- Meal timing: 3 meals + 2–3 snacks to prevent spikes
3. Safe Exercise
- 150 mins/week of walking, swimming, prenatal yoga
- Avoid: High-impact activities after 1st trimester
4. Medication if Needed
- First-line: Insulin (doesn’t cross placenta)
- Oral meds: Metformin may be used off-label
After Delivery
- Most women return to normal glucose levels postpartum.
- 6–12 weeks postpartum: Repeat 75g OGTT to check for prediabetes/diabetes.
- Long-term:
- Annual glucose screening
- Weight management (↓ diabetes risk by 58%)
- Breastfeeding → Improves glucose metabolism
Key Takeaways
✅ GDM is common but manageable with early detection.
✅ Diet + exercise control 90% of cases.
✅ Postpartum vigilance prevents type 2 diabetes.
”A healthy pregnancy starts with balanced blood sugar—for you and your baby.”
(Individualized care is essential.)
(Sources: ADA, ACOG, NIH)