What are Diabetes Canada's recommendations for postpartum screening and management in women with a history of Gestational Diabetes Mellitus (GDM)?

Diabetes Canada's Recommendations for Postpartum Screening in Women with GDM

Women with a history of gestational diabetes mellitus (GDM) should be screened at 4-12 weeks postpartum using a 75-g oral glucose tolerance test (OGTT) with non-pregnancy diagnostic criteria, followed by lifelong screening for diabetes every 1-3 years. 1, 2

Postpartum Screening Protocol

Initial Postpartum Testing (4-12 weeks)

• A 75-g OGTT is the recommended screening test at 4-12 weeks postpartum 1, 2
• HbA1c is not recommended for initial postpartum screening because:
  • Values may be persistently impacted by increased red blood cell turnover during pregnancy
  • Blood loss at delivery can affect results
  • The preceding 3-month glucose profile may not be representative 1
• Diagnostic criteria for the 75-g OGTT (using non-pregnancy criteria):
  • Diabetes: Fasting plasma glucose ≥126 mg/dL (7.0 mmol/L) or 2-h plasma glucose ≥200 mg/dL (11.1 mmol/L)
  • If only one abnormal value meets diabetes criteria, the test should be repeated to confirm 1

Long-term Follow-up

• Lifelong screening for diabetes development every 1-3 years 1, 2
• Any recommended glycemic test can be used for ongoing evaluation:
  • Annual HbA1c
  • Annual fasting plasma glucose
  • Triennial 75-g OGTT 1

Rationale for Screening

• GDM often represents previously undiagnosed prediabetes, type 2 diabetes, or developing type 1 diabetes 1
• Women with GDM have a 50-60% lifetime risk of developing type 2 diabetes 1, 2
• Risk of progression to diabetes increases linearly over time 1, 2

Management Recommendations for Women with Prediabetes

• Intensive lifestyle interventions and/or metformin should be offered to women with overweight/obesity and history of GDM who develop prediabetes 1, 2
• The Diabetes Prevention Program found that progression to diabetes can be delayed or prevented by intervention 1
• In the Nurses' Health Study II, diabetes risk after GDM was significantly lower in women who followed healthy eating patterns 1

Additional Postpartum Recommendations

• Breastfeeding is recommended to reduce the risk of maternal type 2 diabetes 1, 2
• A contraceptive plan should be discussed and implemented 1
• Preconception screening for diabetes should be sought before future pregnancies 1, 2
• Postpartum care should include psychosocial assessment and support for self-care 1, 2

Common Pitfalls in Postpartum GDM Management

1. Poor screening completion rates: Only about 40-53% of women complete the recommended 6-12 week postpartum OGTT 3, 4. Team-based approaches to care can improve screening rates from 39% to 77% 3.

2. Relying on HbA1c alone for initial postpartum screening: HbA1c may be falsely lowered due to pregnancy-related changes in red blood cell turnover and postpartum blood loss 1.

3. Failure to provide long-term follow-up: Many women are lost to follow-up after the initial postpartum period, despite their high lifetime risk of developing type 2 diabetes 1.

4. Missing opportunities for diabetes prevention: Women with prediabetes after GDM benefit significantly from lifestyle interventions and/or metformin, but these interventions are often not implemented 1, 2.

By following these evidence-based recommendations for postpartum screening and management, healthcare providers can significantly reduce the risk of type 2 diabetes development in women with a history of GDM.