Study Finds Fish Oil During Pregnancy Alters Two Childhood Brain Metabolic Markers

Taking fish oil during pregnancy may have long-lasting effects on a child's brain, but it does not necessarily improve brain function, according to a new randomized controlled trial accepted for publication in Translational Psychiatry.

Researchers found that children whose mothers took omega-3 fish oil supplements during pregnancy showed small differences in brain metabolism at 10 years of age. The changes made their brain activity look slightly more like that of adults. However, the researchers stress that this does not mean the brain developed faster or worked better.

The study used data from the COPSAC-2010 trial, which included 700 pregnant women. From the 24th week of pregnancy until one week after delivery, women received either fish oil supplements or an olive oil placebo. Around 10 years later, 460 children underwent advanced MRI brain scans.

The scans showed that children whose mothers took fish oil had slightly lower blood flow in the brain and used slightly less oxygen, both signs of brain metabolism. However, levels of lactate, another marker of brain activity, remained unchanged.

To better understand the findings, researchers compared the children's brain scans with those of healthy adults. The children exposed to fish oil had brain metabolism that looked slightly closer to adult patterns. Still, the researchers say this does not prove that fish oil speeds up brain development or makes the brain more efficient.

Importantly, the study found no differences in memory, thinking skills, or mental health between children whose mothers took fish oil and those who received the placebo.

The researchers say the changes in brain metabolism were small, and more studies are needed to find out whether they have any real health or developmental benefits.

For now, the results suggest that taking fish oil during pregnancy may slightly influence how a child's brain uses energy, but it does not appear to improve cognitive or behavioral outcomes.

REFERENCE: Hernández-Lorca, M., Vestergaard, M., Ambrosen, K., Raghava, J., Lindberg, U., Jepsen, J. M., Rosenberg, J., Lemvigh, C., Mohammadzadeh, P., Glenthøj, B., Chawes, B., Vinding, R., Bønnelykke, K., Larsson, H., & Ebdrup, B. (2026). Fish oil-derived fatty acids in pregnancy and brain metabolism in middle childhood: Results from a randomized controlled trial. Translational Psychiatry. DOI: 10.1038/s41398-026-04173-5, https://www.nature.com/articles/s41398-026-04173-5