What is the risk of developing diabetes in women with a history of gestational diabetes (GDM)?

Risk of Developing Diabetes After Gestational Diabetes

Women with a history of gestational diabetes (GDM) have a 50-60% lifetime risk of developing type 2 diabetes, with risk increasing linearly over time: approximately 20% at 10 years, 30% at 20 years, 40% at 30 years, 50% at 40 years, and 60% at 50 years after the GDM pregnancy. 1

Risk Progression Timeline

• Women with GDM have a 10-fold increased risk of developing type 2 diabetes compared to women without GDM 1
• The risk increases linearly throughout a woman's lifetime 1:
  • 20% at 10 years post-GDM
  • 30% at 20 years post-GDM
  • 40% at 30 years post-GDM
  • 50% at 40 years post-GDM
  • 60% at 50 years post-GDM

Risk Factors That Increase Diabetes Risk After GDM

Several factors influence the likelihood of progression to type 2 diabetes:

• Multiple GDM pregnancies: Having GDM in two pregnancies significantly increases risk compared to a single GDM pregnancy (hazard ratios ranging from 4.35 to 15.8-fold) 1
• Obesity and weight gain: Development of type 2 diabetes is 18% higher per unit of BMI increase from prepregnancy BMI 1
• Severity of glucose intolerance during pregnancy: More severe hyperglycemia during pregnancy correlates with higher diabetes risk 1, 2
• Ethnicity: Certain ethnic backgrounds have higher conversion rates 3, 2
• Family history of diabetes: First-degree relatives with diabetes increase risk 3, 2
• Age: Older maternal age at time of GDM diagnosis increases risk 3, 2
• Parity: Higher number of pregnancies increases risk 2

Preventive Strategies

Evidence shows that progression to diabetes can be delayed or prevented:

• Lifestyle interventions: Healthy eating patterns significantly lower subsequent diabetes risk 1
• Weight management: Effective weight management after GDM is crucial for diabetes prevention 1
• Metformin and intensive lifestyle intervention: Both approaches are effective in preventing progression to diabetes in women with prediabetes and history of GDM 1
  • Only 5-6 individuals with prediabetes and GDM history need to be treated with either intervention to prevent one case of diabetes over 3 years 1
  • Lifestyle intervention reduced progression to diabetes by 35% over 10 years 1
  • Metformin reduced progression to diabetes by 40% over 10 years 1
• Breastfeeding: Reduces the risk of developing type 2 diabetes in mothers with previous GDM 1

Recommended Follow-up

• Initial postpartum testing with 75-g OGTT at 4-12 weeks after delivery 1
• Ongoing screening for prediabetes or type 2 diabetes every 1-3 years, even if initial postpartum results are normal 1
• Screening can be performed with any recommended glycemic test:
  • Annual A1C
  • Annual fasting plasma glucose
  • Triennial 75-g OGTT using non-pregnant thresholds 1

Common Pitfalls in Post-GDM Care

• Poor communication between obstetric providers and primary care providers: This has been identified as a major barrier to appropriate follow-up screening 4
• Lack of documentation: Less than half (45.8%) of women with GDM have this history properly documented in their electronic medical records 4
• Relying only on fasting glucose: Measuring only fasting plasma glucose postpartum is not sufficiently sensitive to identify all women with impaired glucose tolerance or type 2 diabetes 1
• Inadequate long-term follow-up: Despite awareness of the high risk, clinicians often fail to routinely assess and screen patients with GDM history 4

Understanding this substantial risk of future diabetes is crucial for implementing appropriate screening and preventive measures in women with a history of GDM.