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Can maternal metformin protect the developing fetal brain?

Ibarra C, Fekry B, Ugartemendia L, Boggess K, Suchting R, Goetzl L

American journal of obstetrics and gynecology, 2026

40 participants · 3 citations

Abstract

Background: Maternal diabetes is associated with an increased risk of autism spectrum disorder and attention-deficit hyperactivity disorder. Metformin has an emerging role as a neuroprotective agent, both in perinatal preclinical models and in nonobstetric clinical trials. Metformin crosses the placenta and fetal exposure has potential risks and benefits. New techniques allow for isolation of extracellular vesicles that originate from fetal neurons and cross the placenta into maternal blood, providing a window into ongoing neurodevelopment.

Objective: To determine if maternal treatment with metformin for maternal diabetes had beneficial effects on biomarkers of fetal brain health.

Study design: A nested case-control study was performed on maternal samples from a randomized controlled trial of metformin (1000 mg twice daily) + insulin vs insulin only for perinatal type 2 diabetes mellitus (n=40 in each group) or gestational diabetes mellitus. Fetal neuronally derived extracellular vesicles were purified from maternal serum collected at 24 to 30 weeks. Sirtuin-1, tumor necrosis factor-alpha and Bcl-2-associated X protein were quantified. Correlation between vesicle and fetal brain concentrations of biomarkers was validated in a second set of individuals undergoing voluntary pregnancy termination. Generalized linear modeling was performed to evaluate the effect of metformin treatment on fetal neuronal markers.

Results: In-utero exposure to metformin was associated with a 39%…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 40 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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