Guideline Recommendations for Gestational Diabetes Management

Lifestyle Management

Lifestyle modification with medical nutrition therapy and regular physical activity is the first‑line approach; insulin is added only when glycemic targets are not met, because it has proven safety and improves perinatal outcomes (high‑quality randomized evidence). 1
Medical nutrition therapy, designed by a registered dietitian, should provide roughly 1,800–2,000 kcal/day (≈200 g carbohydrate) to support fetal and maternal health while meeting glucose goals (moderate evidence). 3
At least 175 g of carbohydrate per day (≈35 % of a 2,000‑kcal diet) should be consumed, emphasizing nutrient‑dense, high‑quality sources to limit post‑prandial spikes (moderate evidence). 2
Women should perform ≥150 minutes of moderate‑intensity aerobic exercise each week, distributed across days, which improves glucose control and lowers insulin requirements (moderate evidence). 4
Glucose monitoring targets are: fasting < 95 mg/dL and either 1‑hour post‑prandial < 140 mg/dL or 2‑hour post‑prandial < 120 mg/dL (moderate evidence). 5
Approximately 70–85 % of pregnant women achieve glycemic control with lifestyle measures alone (moderate evidence). 3

Insulin is the only FDA‑approved medication for gestational diabetes and is the recommended first‑line pharmacologic therapy (high‑quality evidence). 1
Insulin does not cross the placenta to a measurable extent, eliminating fetal exposure concerns (moderate evidence). 3
Large randomized trials have demonstrated that insulin therapy improves perinatal outcomes compared with no treatment (high‑quality evidence). 1
Insulin can be titrated without upper limits to achieve individualized glycemic targets (moderate evidence). 7
Recommended insulin regimens include:
- Long‑acting basal insulin (NPH, detemir, or glargine)
- Rapid‑acting prandial insulin (lispro or aspart) for post‑prandial hyperglycemia
- Both multiple‑daily injections and insulin pump therapy are acceptable delivery methods (moderate evidence). 5

Metformin and glyburide are not first‑line agents because they cross the placenta and have concerning long‑term offspring data; they may be considered only when insulin is unavailable after thorough risk‑benefit counseling (moderate evidence). 1

Metformin crosses the placenta, achieving cord‑blood concentrations equal to or higher than maternal levels (moderate evidence). 1
Nine‑year follow‑up shows offspring exposed to metformin have higher body‑mass index, waist‑to‑height ratio, and waist circumference than those exposed to insulin (moderate evidence). 1
About 25–28 % of women using metformin will still require supplemental insulin to reach glycemic goals (moderate evidence). 8
Metformin is contraindicated in women with hypertensive disorders, pre‑eclampsia, or risk of intra‑uterine growth restriction because of potential fetal growth restriction or acidosis (moderate evidence). 1

Glyburide reaches 50–70 % of maternal concentrations in cord blood (moderate evidence). 2
Use of glyburide is linked to higher rates of neonatal hypoglycemia, macrosomia, and increased abdominal circumference compared with insulin or metformin (moderate evidence). 1
Approximately 23 % of women on glyburide will need supplemental insulin (moderate evidence). 8
No long‑term safety data are available for children exposed to glyburide in utero (moderate evidence). 1

Metformin should be avoided in women with hypertensive disorders or at risk for fetal growth restriction (moderate evidence). 1
Continuation of metformin started before pregnancy for polycystic ovary syndrome is not recommended, as it does not prevent gestational diabetes (moderate evidence). 8
Urine ketone testing should be performed in fasting women, especially those severely restricting carbohydrates to avoid insulin, to detect ketosis early (moderate evidence). 1
Excessive carbohydrate restriction should be avoided; replacing carbs with fat can increase lipolysis, free fatty acids, and worsen insulin resistance (moderate evidence). 1

All women with gestational diabetes should undergo a 2‑hour 75‑g oral glucose tolerance test between 4 and 12 weeks after delivery to screen for persistent diabetes (moderate evidence). 5
Lifelong diabetes surveillance in primary care is essential because women with prior gestational diabetes have a markedly increased risk of developing type 2 diabetes (high‑quality evidence). 9
Breastfeeding is strongly encouraged; insulin‑treated women may need additional carbohydrate intake during lactation to prevent hypoglycemia (moderate evidence). 10