Overview
The podcast discusses the latest evidence on metformin use for gestational diabetes and type 2 diabetes in pregnancy, highlighting results from recent randomized trials and ongoing research needs. Dr. Denise Feig reviews trial findings, clinical implications, and unresolved questions regarding short- and long-term outcomes for mothers and offspring.
Importance of Gestational Diabetes
- Gestational diabetes affects 7–18% of pregnancies, depending on criteria and population.
- It is linked to adverse outcomes: preeclampsia, higher C-section rates, macrosomia, birth injury, neonatal hypoglycemia, and ICU admission.
- Long-term risks exist for both mother and child.
Metformin in Gestational Diabetes: Evidence and Practice
- The 2008 MIG trial found metformin as safe as insulin, with no difference in composite neonatal outcomes and higher maternal preference for metformin.
- Metformin is first-line for gestational diabetes in the UK/Europe, but not recommended in the US.
EMERGE Trial Findings
- Early initiation of metformin (at diagnosis) versus usual care (insulin after lifestyle intervention failure) was studied.
- No significant difference in the composite primary outcome, but early metformin led to better fasting glucose, lower hemoglobin A1c, reduced maternal weight gain, and fewer large-for-gestational-age (LGA) infants.
- Early metformin initiation is safe and may offer improved glycemic control.
Metformin in Type 2 Diabetes During Pregnancy
- The MiTy trial (Feig) tested adding metformin to insulin in type 2 diabetes during pregnancy.
- No difference in serious neonatal outcomes, but better maternal glycemic control, lower weight gain, reduced C-section rates, lower insulin requirements, and improved infant size outcomes.
- The MOMPOD trial (Boggess et al.) also showed better glycemic control, lower LGA rates, and reduced birth weight but did not find reductions in C-section, insulin dose, or maternal weight gain.
Remaining Research Questions
- It remains unclear whether early metformin is superior to post-lifestyle intervention metformin in gestational diabetes.
- Discrepancies between MiTy and MOMPOD may be due to population, practice patterns, or compliance; pooled analyses are planned.
- The long-term effects of in-utero metformin exposure on offspring risk for obesity and diabetes are uncertain; ongoing follow-up studies are underway.
Clinical Takeaways
- Current data support a role for metformin in gestational and type 2 diabetes during pregnancy, particularly for women needing high insulin doses.
- Long-term offspring outcomes require further study before definitive clinical guidelines can be established.