long term

BACKGROUND AND PURPOSE: 

• Metformin in Gestational diabetes (MiG) trial 
  • RCT of women with GDM, randomized to either metformin (plus supplemental insulin if required) or insulin 
  • Similar outcomes although metformin group had increased rate of preterm birth (12/1% vs 7.6%, p=0.04) and neonates with lower rates of severe hypoglycemia (3.3% vs 8.1%, p=0.009) 
  • Long-term offspring follow-up (TOFU) data are lacking and studies are ongoing  
• Outcomes at 2 years of age in offspring of women with GDM treated with metformin showed similar total body fat percent, but greater subscapular and biceps skinfolds, as well larger upper arm circumferences  
• Rowan et al. (BMJ Open Diabetes Research & Care, 2018) present the 7 year follow up data from the MiG trial

METHODS: 

• Longitudinal follow-up of women recruited to MiG-TOFU study 
• Women were randomized into groups that received 
  • Metformin  
  • Insulin 
  • Matching control 
• Children were assessed in Adelaide (7 year follow up) and then Auckland (9 year follow up) using multiple tools 
  • Anthropometry 
  • Bioimpedance analysis (BIA) 
  • Dual-energy X-ray absorptiometry (DXA) 
  • Magnetic resonance imaging (MRI) 
  • Fasting bloods 

RESULTS: 

• Total participants: 208 
  • 109 Adelaide (7 year) and 99 Auckland (9 year)  
• There were no differences in offspring measures at 7 years 
• At 9 years in Auckland, metformin offspring were 
  • Larger by measures of weight, arm and waist circumferences, waist:height (p<0.05) 
  • BMI, triceps skinfold (p=0.05) 
  • DXA fat mass and lean mass (p=0.07) 
  • MRI abdominal fat volume (p=0.051) 
• All other measures were similar 

CONCLUSION:  

• Metformin or insulin for GDM was associated with similar offspring total and abdominal body fat percent and metabolic measures at 7-9 years 
• However, metformin-exposed children were larger at 9 years 
• Authors state that overall, data related to long-term metformin use is reassuring but further research is needed to understand the findings at 9 years 

Learn More – Primary Sources: 

Metformin in gestational diabetes: the offspring follow-up (MiG TOFU): body composition and metabolic outcomes at 7-9 years of age.

Related ObG Topics:

ACOG and SMFM Both Release Guidance on Gestational Diabetes – Insulin vs Metformin for First-Line Therapy?

Metformin in Pregnancy

Are Metformin or Statins Associated with Increased Risk for Ovarian Cancer in Women with Type 2 Diabetes?