Metformin use in GDM reduces neonatal hypoglycaemia and lowers birthweight. The analysis, published in Diabetic Medicine, systematically reviewed randomized controlled trials that evaluated maternal, neonatal, and long-term outcomes associated with metformin therapy in GDM.

Ten randomized controlled trials were included in the review. The primary outcomes were neonatal hypoglycaemia, birthweight, and later metabolic measures. Data were synthesized using the inverse variance heterogeneity model after study quality was assessed with RoB 2.0 for randomized controlled trials and ROBINS-I for follow-up studies.

Metformin lowered the risk of neonatal hypoglycaemia (odds ratio 0.65; 95% confidence interval 0.46-0.92) and reduced birthweight (mean difference −68.96 g; 95% confidence interval −108.34 to −29.57). A non-significant trend toward lower risk of large-for-gestational-age infants was observed. Long-term outcomes such as prediabetes, diabetes, or insulin resistance in children showed no significant differences across treatment groups.

These findings indicate that metformin is a safe and effective alternative to insulin for GDM management. However, the long-term metabolic impact on offspring remains uncertain, highlighting the need for extended follow-up studies.