Gestational Diabetes Management
A 28-year-old G1P0 at 26 weeks gestation has a 1-hour glucose challenge test of 160 mg/dL, followed by a 3-hour glucose tolerance test showing fasting 95 mg/dL, 1-hour 190 mg/dL, 2-hour 165 mg/dL, and 3-hour 140 mg/dL. She is diagnosed with gestational diabetes. She is 5'6", weighs 180 lb, and has no other medical problems. She is motivated to manage with diet and exercise.
1. What are the glucose targets for gestational diabetes, and how would you monitor her?
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The recommended glucose targets for GDM are fasting <95 mg/dL, 1-hour postprandial <140 mg/dL, or 2-hour postprandial <120 mg/dL. She should monitor her blood glucose four times daily (fasting and after each meal) initially. She should keep a log and review with her provider weekly. She also needs nutritional counseling and regular exercise. If she meets targets with lifestyle, continue; if not, start insulin (preferred) or oral agents like glyburide or metformin (though insulin is first-line). She should also have an ultrasound for fetal growth and amniotic fluid assessment in the third trimester.
2. If she requires insulin, what regimen would you start, and what are the risks of poorly controlled GDM?
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If she requires insulin, a basal-bolus regimen is preferred: intermediate-acting insulin (NPH) or long-acting (detemir) at bedtime for fasting hyperglycemia, and rapid-acting insulin (lispro) before meals for postprandial hyperglycemia. Start with low doses (e.g., 0.1-0.2 units/kg/day) and titrate. Risks of poorly controlled GDM include macrosomia, shoulder dystocia, preeclampsia, polyhydramnios, stillbirth, and neonatal hypoglycemia. She should be counseled about these risks and the importance of tight control. She should also have a postpartum glucose tolerance test at 6-12 weeks to screen for type 2 diabetes.