Gestational Diabetes Mellitus (GDM)

Queensland Clinical Guidelines Endorsement

• The Queensland Clinical Guidelines are endorsed by the Queensland Clinical Guidelines Steering Committee.

Risk Factors for Gestational Diabetes Mellitus (GDM)

• Major risk factors for GDM include obesity, advanced age, family history of diabetes, and certain ethnic backgrounds.
• Ethnicities with increased risk for GDM include Indigenous Australians, Torres Strait Islanders, some Asian populations, Pacific Islanders, and Middle Eastern descent.

Screening and Diagnosis of GDM

• A standard test used for screening and diagnosing GDM during the first trimester is the Oral Glucose Tolerance Test (OGTT).
• Fasting target for capillary blood glucose levels in GDM management is typically ≤5.0 mmol/L.

Timing of Testing

• An OGTT should be performed between 24 and 28 weeks of pregnancy.
• Diagnostic criteria for GDM include a fasting blood glucose level of ≥5.1 mmol/L during an OGTT.

Body Mass Index (BMI) and GDM

• A BMI of ≥30 kg/m² is considered a risk factor for developing GDM.

Monitoring in GDM Management

• Postprandial capillary blood glucose level self-monitoring helps in managing GDM by managing glycemic control after meals.
• If diabetes is suspected in the third trimester, further testing and monitoring should be conducted.

Birth Recommendations

• For women with GDM requiring metformin and/or insulin, the recommended mode of birth is vaginal unless medical indications suggest otherwise.

Medication Management Before Procedures

• Metformin should be ceased at least 24 hours before any procedure requiring anesthetic or where fasting is necessary.

Induction of Labour (IOL) Guidance

• For morning IOL with GDM requiring insulin, if labor is not established, administer short-acting insulin as needed based on blood glucose levels.
• For afternoon IOL, continue normal insulin regimen unless instructed otherwise by healthcare providers.
• If a woman is on an IV insulin infusion and labor is not established, infusion rates should be adjusted based on continuous glucose monitoring.

Intrapatum Management

• If a woman with GDM has a blood glucose level (BGL) between 4.0–7.0 mmol/L during intrapartum management, routine monitoring should continue.
• If the BGL is <4.0 mmol/L, treatment should be initiated to raise glucose levels, typically through oral glucose or IV dextrose.

Postpartum Management

• Metformin and/or insulin should be ceased for women with GDM immediately after the birth of the placenta.
• In the postpartum period, blood glucose levels should be monitored 1–2 times weekly for women with a history of GDM.
• Recommended postpartum care includes assessment of glucose levels and education regarding diabetes management and lifestyle modifications.