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Metformin use in gestational diabetes mellitus and neonatal outcomes: a systematic review and meta-analysis on the risk of small for gestational age

Zhang W, Ren L, Du J, Sun R, Zhao W, Song X, Jiang S, Wang Z et al.

Frontiers in medicine, 2025

115,192 participants · 1 citation

Abstract

Purpose: It remains unclear whether maternal metformin use in gestational diabetes mellitus (GDM) is associated with an increased risk of small-for-gestational-age (SGA) newborns.

Methods and results: A systematic literature search was conducted across PubMed, Embase, and the Cochrane Library up to September 1, 2024. Nineteen studies (n = 115,192 participants), comprising randomized controlled trials and cohort studies, were included. Two evaluators independently assessed eligibility and bias risk. Maternal use of metformin for GDM was not significantly associated with SGA incidence in newborns (OR = 1.10, 95% CI: 0.97-1.24, p = 0.14). No notable differences were observed compared to insulin-treated (n = 27,622, OR = 1.25, 95% CI: 0.91-1.73, p = 0.17) or placebo groups (n = 1,685, OR = 1.36, 95% CI: 0.80-2.32, p = 0.26). However, two studies (n = 554) indicated a lower SGA incidence with metformin than with diet modification therapy (OR = 0.50, 95% CI: 0.29-0.87, p = 0.01).

Conclusions: Maternal metformin use in the management of GDM doesn't increase SGA risk in offspring, suggesting its relative safety and effectiveness in this context. Further research is required to explore metformin's long-term effects of metformin on offspring of mothers with GDM.

Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420251141984, identifier CRD420251141984.

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 115,192 participants or records.

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