prevent-gestational-diabetes

Prevent Gestational Diabetes

Reduce GDM risk through diet and monitoring; manage confirmed GDM with evidence-based protocol.

Why This Is Best Practice

Adopted by: ACOG, USPSTF, ADA, WHO — universal GDM screening at 24–28 weeks is standard of care globally. Impact: GDM affects 6–9% of pregnancies in the US (CDC 2022). Lifestyle intervention reduces GDM incidence by 36% in high-risk women (Cochrane 2017, 23 RCTs). Untreated GDM increases macrosomia risk 4×, C-section risk 2×, and neonatal hypoglycemia risk 3×. Why best: GDM is largely asymptomatic; risk reduction requires proactive dietary and activity changes before diagnosis.

Steps

1. Know your risk factors: BMI >25, prior GDM, family history of DM2, PCOS, previous macrosomic baby (>9 lbs), age >35.
2. Prevention strategy (preemptive, weeks 8–24):
   • Low glycemic index diet: choose whole grains, legumes, non-starchy vegetables over refined carbs
   • Distribute carbohydrates across 3 small meals + 2–3 snacks; avoid large carb loads
   • 150 min/week moderate exercise (walking after meals blunts postprandial glucose spikes)
   • Target gestational weight gain within IOM guidelines
3. Screening (weeks 24–28, all pregnancies):
   • 1-hour glucose challenge test (GCT): 50g oral glucose load; threshold >130–140 mg/dL triggers 3-hour OGTT
   • High-risk women: screen at first prenatal visit AND repeat at 24–28 weeks
4. If GDM diagnosed (OGTT thresholds met):
   • Start self-monitoring blood glucose: fasting <95 mg/dL; 1hr postmeal <140 mg/dL; 2hr <120 mg/dL
   • Nutritional counseling with registered dietitian — distribute 175g+ carbs across day; avoid fasting >8–10 hours
   • 70% of GDM managed with diet/exercise alone; insulin started if targets not met in 1–2 weeks
5. Postpartum: retest with 75g OGTT at 6–12 weeks postpartum (GDM → 50% DM2 risk within 10 years).

Rules

• Never skip GDM screening even in "healthy" patients — 40% of GDM occurs in women with no identifiable risk factors.
• Do not restrict calories below 1,800 kcal/day with GDM — adequate nutrition for fetal growth is essential.
• Insulin is preferred over metformin in pregnancy (crosses placenta; long-term neonatal effects uncertain per ACOG 2018).

Examples

Post-meal glucose management: 15-minute walk after each meal reduces 1-hour postprandial glucose by ~20–30 mg/dL (DiPietro et al., 2015). Snack pairing: Apple (carb) + almond butter (protein/fat) — blunts glucose spike vs. apple alone.

Common Mistakes

• Treating GDM as "mild diabetes" — uncontrolled GDM causes macrosomia, shoulder dystocia, and neonatal hypoglycemia.
• Cutting all carbs — very low carb causes starvation ketosis, which harms fetal brain development.
• Not monitoring fasting glucose — fasting hyperglycemia is the most common pattern missed with diet changes alone.

Health Disclaimer: Gestational diabetes management requires supervision by an OB-GYN, maternal-fetal medicine specialist, or endocrinologist. Insulin initiation and dose adjustment must be medically supervised.