Pregnancy Omega-3 Levels Shape Children’s Cognitive Trajectories for a Decade

A decade-long study of Spanish children has revealed that the omega-3 fatty acids circulating in a newborn’s umbilical cord blood are linked to the way their cognitive abilities unfold over the following ten years, with different fatty acids leaving distinctly different fingerprints on attention, working memory, and reasoning. The research, published in the European Journal of Epidemiology, followed nearly a thousand children from birth into adolescence and suggests that the timing of a fatty acid’s influence on the developing brain may matter as much as its presence.

The study drew on the Spanish Environment and Childhood (INMA) project, a population-based birth cohort established between 2003 and 2008 across four regions of Spain: Asturias, Gipuzkoa in the Basque Country, Sabadell in Catalonia, and Valencia. From 2,644 eligible women recruited during first-trimester prenatal visits, the researchers measured omega-3 fatty acid proportions in the cord plasma of 953 newborns, ultimately analysing data from 716 mother-child pairs who had at least one valid cognitive assessment during follow-up. Cord blood is a powerful biomarker because it reflects maternal diet and fatty acid transfer to the foetus during the third trimester, a critical window characterised by the rapid foetal brain growth spurt and the highest rate of polyunsaturated fatty acid accretion in development.

The team focused on three omega-3 fatty acids with distinct biological roles. Docosahexaenoic acid, or DHA, is the most abundant omega-3 in the brain and serves as the primary structural component of neuronal membranes, supporting synaptogenesis, membrane fluidity, signal transduction, and myelination, particularly in the prefrontal cortex. Eicosapentaenoic acid, or EPA, protects brain health mainly by reducing neuroinflammation and facilitating placental DHA transport. Alpha-linolenic acid, or ALA, is an essential fatty acid that mammals cannot synthesise de novo and which provides direct neuroprotection while supporting neuronal growth and plasticity. Because the human conversion of ALA to DHA is marginal and to EPA inefficient, direct dietary intake of these compounds during pregnancy is necessary.

Cognitive function was assessed repeatedly using internationally validated computer-based neuropsychological tests. Inattentiveness was measured at approximately ages 5, 7, and 11 using the Conners’ Kiddie Continuous Performance Test and the Attention Network Test, with higher values of hit reaction time standard error indicating greater inattentiveness. Working memory was evaluated at ages 7, 11, and 15 with the N-back task, using detectability in the demanding 3-back condition as the primary outcome. Fluid intelligence was assessed at around ages 9 and 15 with Raven’s Progressive Matrices and a Spanish adaptation of the Test of Primary Mental Abilities. All scores were converted to age-specific z-scores to allow comparison across different instruments and follow-up waves.

The statistical approach was what set this study apart from most previous nutritional epidemiology. Rather than comparing cognitive test results at isolated time points, the researchers used linear mixed-effects models with interaction terms between child age and fatty acid exposure, allowing them to model entire developmental trajectories from age 5 to 15. Models included cohort-level and individual-level random effects, and were adjusted for child sex, maternal age, maternal education, preconception body mass index, Mediterranean diet adherence, and alcohol consumption during pregnancy. Confounders were selected using a directed acyclic graph, and missing covariate data were handled through multiple imputation.

The results revealed a striking divergence between ALA and DHA. In overall models averaging across the whole follow-up period, higher cord plasma proportions of both ALA and DHA were associated with lower inattentiveness, and higher DHA was linked to better working memory. But the trajectory models told a more nuanced story. Children with higher prenatal ALA exposure showed significant early advantages in attention and fluid intelligence, with predicted differences between high and low exposure groups reaching 0.76 standard deviations for fluid intelligence at age 5. Yet these advantages attenuated and even reversed over time: by age 15, children with higher ALA showed slightly worse fluid intelligence scores than their lower-exposure peers, as children with lower prenatal ALA appeared to catch up and overtake them.

DHA displayed the opposite temporal pattern. Children with higher cord plasma DHA began with markedly better working memory in early childhood, with a predicted advantage of 0.54 standard deviations at age 5, but this gap gradually converged as lower-exposure children improved. Meanwhile, the benefits of DHA for attention and fluid intelligence emerged later and grew steadily stronger: children with higher DHA showed progressively less inattentiveness from age 7 onward, with the predicted difference widening to 0.67 standard deviations by age 15, and better fluid intelligence emerging by adolescence. EPA, present at very low relative abundance in cord plasma, showed no significant associations with any cognitive outcome.

The authors propose biological explanations for these divergent patterns. ALA’s early boost may reflect its influence on neuronal membrane fluidity, gene expression, and synaptic plasticity during the period when neural networks are rapidly expanding, with its effects later swamped by the growing influence of children’s own diets and postnatal environments. DHA, by contrast, is directly incorporated into neuronal membranes of the prefrontal cortex, a region that begins functioning in early childhood but continues structural refinement through adolescence. A stable structural foundation laid down during gestation could therefore support the progressive maturation of attentional control and executive networks, producing advantages that become increasingly evident as higher-order cognitive functions consolidate. The early working memory advantage of DHA is consistent with the heavy reliance of that function on the dorsolateral prefrontal cortex, a region characterised by rapid DHA accretion during late gestation.

The study’s robustness was tested extensively. Results remained virtually identical across sensitivity analyses adjusting for postnatal fish and nut intake, breastfeeding duration, maternal verbal IQ, mercury exposure, and smoking during pregnancy. Applying inverse probability weighting to account for attrition bias produced consistent trajectories and even strengthened some associations, including a progressive longitudinal gain in working memory for the highest ALA group that reached statistical significance after additional adjustment. Findings also survived false discovery rate correction. The researchers acknowledge limitations, however: cord plasma fatty acids were expressed as relative percentages rather than absolute concentrations, cord levels reflect exposure near delivery rather than cumulative intake across pregnancy, and the observational design cannot establish strict causality, even though the use of an objective prenatal biomarker preceding outcomes by more than a decade establishes clear temporality.

The implications reach beyond academic interest. The findings underscore the importance of distinguishing between individual omega-3 fatty acids when evaluating their role in neurodevelopment, rather than treating omega-3 as a single nutritional category, and they highlight the need for long-term follow-up to capture cognitive associations that may be delayed by years. For pregnant women and clinicians, the study adds to existing evidence that maternal nutrition during the third trimester, when the foetal brain undergoes its most intense period of fatty acid accumulation, may have consequences that unfold across an entire decade of cognitive development. The authors call for replication in diverse populations, integration of postnatal biomarker data to disentangle prenatal from postnatal influences, and neuroimaging studies to identify the brain structural and functional mediators underlying these distinct temporal trajectories.

Subject of Research: Associations between prenatal omega-3 fatty acid exposure measured in cord plasma and longitudinal cognitive development in children

Article Title: Omega-3 cord plasma proportions and cognitive function trajectories from 5 to 15 years of age: a population-based cohort study

Article References: Pinar-Martí, A., Ayala-Aldana, N., Bernardo-Castro, S., Manidis, A., Cadman, T., Sala-Vila, A., Lázaro, I., Lertxundi, N., Subiza-Pérez, M., González-Safont, L., Vioque, J., Riaño-Galán, I., Rodríguez-Dehli, C., López-Sabater, M. C., Vrijheid, M., Guxens, M., Foraster, M., & Julvez, J. (2026). Omega-3 cord plasma proportions and cognitive function trajectories from 5 to 15 years of age: a population-based cohort study. European Journal of Epidemiology. https://doi.org/10.1007/s10654-026-01461-8

Image Credits: AI Generated

DOI: 10.1007/s10654-026-01461-8

Keywords: omega-3 fatty acids, DHA, ALA, prenatal nutrition, cognitive development, neurodevelopment, working memory, attention, fluid intelligence, birth cohort, cord blood, childhood adolescence