Gestational Diabetes Management

Introduction to Management

• The American Diabetes Association recommends that treatment of gestational diabetes mellitus (GDM) should begin with lifestyle modifications, including nutritional therapy and physical activity, adding insulin when necessary to achieve glycemic targets, as insulin is the preferred medication because it does not cross the placenta in measurable quantities 1, 2

Glycemic Targets

• The recommended targets for women with GDM and pre-existing diabetes are: fasting < 95 mg/dL, one hour postprandial < 140 mg/dL, and two hours postprandial < 120 mg/dL 2, 3, 4
• For pre-existing diabetes in pregnancy, the ideal HbA1c target is < 6% if it can be achieved without significant hypoglycemia, but may be relaxed to < 7% if necessary to prevent hypoglycemia 2, 3

Medical Nutrition Therapy

• Medical nutrition therapy is a cornerstone of GDM treatment and should be individualized with the support of a nutritionist 1, 5
• Nutritional recommendations include a minimum of 175g of carbohydrates per day, 71g of protein per day, and 28g of fiber per day, with an emphasis on monounsaturated and polyunsaturated fats, limiting saturated fats, and avoiding trans fats 1, 4, 5, 6

Physical Activity

• At least 150 minutes of moderate-intensity aerobic activity per week is recommended during pregnancy and postpartum, preferably distributed throughout the week 5
• Systematic reviews have demonstrated improvements in glycemic outcomes and reductions in the need to initiate insulin with exercise interventions 4

Pharmacological Treatment

• Approximately 70-85% of women diagnosed with GDM can control the condition with lifestyle modifications alone 1, 7
• Insulin is the preferred medication for treating hyperglycemia in GDM because it does not cross the placenta in measurable quantities 1, 6
• Metformin and glyburide are not recommended as first-line agents because they both cross the placenta to the fetus 6, 7

Monitoring

• Self-monitoring of blood glucose in fasting and postprandial states is recommended for both GDM and pre-existing diabetes in pregnancy to achieve glycemic control 2
• Postprandial monitoring is associated with better glycemic control and lower risk of preeclampsia 2, 3

Postpartum and Prevention of Type 2 Diabetes

• Women with GDM should be tested for persistent diabetes or prediabetes 4-12 weeks postpartum with a 75g OGTT using non-gestational criteria 8
• Women with a history of GDM are at increased risk of conversion to type 2 diabetes over time 8, 9
• Both metformin and intensive lifestyle intervention prevent or delay progression to diabetes in women with a history of GDM 9