What is the recommended glucose range target in Gestational Diabetes Mellitus (GDM)?

Glucose Range Targets in Gestational Diabetes Mellitus (GDM)

The recommended glucose range targets for women with GDM are fasting plasma glucose <95 mg/dL (5.3 mmol/L), 1-hour postprandial glucose <140 mg/dL (7.8 mmol/L), or 2-hour postprandial glucose <120 mg/dL (6.7 mmol/L). 1, 2

Standard Glycemic Targets

• Fasting plasma glucose should be maintained below 95 mg/dL (5.3 mmol/L) 1, 2
• One-hour postprandial glucose should be below 140 mg/dL (7.8 mmol/L) 1, 2
• Two-hour postprandial glucose should be below 120 mg/dL (6.7 mmol/L) 1, 2

These targets are based on recommendations from the American Diabetes Association and the Fifth International Workshop-Conference on Gestational Diabetes Mellitus, which have been consistently maintained in guidelines through 2025 1.

Monitoring Recommendations

• Self-monitoring of blood glucose (SMBG) is essential for evaluating glycemic control in GDM 2
• Blood glucose monitoring should be performed using capillary blood glucose meters that meet accuracy standards 2
• Postprandial measurements should be taken 1-2 hours after beginning the meal 2
• Women should monitor either 1-hour or 2-hour postprandial glucose levels (not necessarily both) 1

A1C Targets in GDM

• The A1C goal in pregnancy is ideally <6% (<42 mmol/mol) if achievable without significant hypoglycemia 1
• The goal may be relaxed to <7% (<53 mmol/mol) if necessary to prevent hypoglycemia 1
• A1C should be used as a secondary measure of glycemic control in pregnancy, after blood glucose monitoring, due to physiological changes in red blood cell turnover during pregnancy 1

Continuous Glucose Monitoring (CGM)

• CGM can help achieve glycemic goals in pregnancy and may be beneficial for GDM management 1
• For patients using CGM, the following targets are recommended:
  • Target sensor glucose range: 63-140 mg/dL (3.5-7.8 mmol/L) with time in range >70% 1
  • Time below range (<63 mg/dL): <4% 1
  • Time below range (<54 mg/dL): <1% 1

Special Considerations

• For women with preexisting type 1 or type 2 diabetes who become pregnant, stricter targets may be recommended 2
• Ultrasound measurement of fetal abdominal circumference can help guide glycemic management decisions - stricter targets may be needed if excessive fetal growth is detected 2
• Some recent research is investigating even more intensive glycemic targets (fasting <90 mg/dL and 1-hour postprandial <120 mg/dL) for overweight and obese women with GDM, though these are not yet standard recommendations 3

Management Approach

• Medical nutrition therapy is the cornerstone of GDM management, with appropriate carbohydrate distribution throughout the day 2
• Physical activity should be encouraged if not contraindicated 2
• If blood glucose targets cannot be achieved with lifestyle modifications alone, insulin therapy should be initiated as the first-line pharmacological treatment 1
• Approximately 70-85% of women diagnosed with GDM can control their condition with lifestyle modification alone 1

Clinical Pearls and Pitfalls

• Postprandial hyperglycemia is a primary driver of macrosomia and other adverse fetal outcomes in GDM 2
• Avoiding excessive carbohydrate restriction that could lead to ketosis is important 2
• Women with greater initial degrees of hyperglycemia may require earlier initiation of pharmacologic therapy 1
• After delivery, all women with GDM should be tested for persistent diabetes or prediabetes at 4-12 weeks postpartum 2, 4

These glucose targets have been established to minimize maternal and fetal/neonatal morbidity and mortality, with consistent recommendations across multiple guidelines and updates through 2025.