EXPOSURE to certain aromatic amines during pregnancy may be associated with differences in infant attention and memory, according to new research.
The study, involving 250 mother-child pairs in the USA, is the first human epidemiological investigation to examine associations between prenatal aromatic amine exposure and cognitive performance during infancy.
Researchers identified links between several chemical exposures and poorer performance on an eye-tracking assessment conducted when infants were approximately 7.5 months old.
Aromatic amines are a group of chemicals used in various consumer products and industrial processes. Although several have recognised carcinogenic properties, their potential effects on early neurodevelopment remain poorly understood.
Researchers combined data from two prospective birth cohorts: the Illinois Kids Development Study and Chemicals in Our Bodies, which together form the ECHO.CA.IL cohort.
The analysis included 250 mother-child pairs, with maternal urine samples collected during the second trimester of pregnancy.
Investigators measured several aromatic amines, including aniline, o/m-toluidine, 4-chloroaniline, o-anisidine, 4,4′-methylenedianiline, and cotinine. These compounds were detected in more than half of participants.
Infant cognition was subsequently assessed using an infrared eye-tracking visual recognition memory task designed to evaluate early attention, information processing, and recognition memory.
Researchers found that higher concentrations of certain aromatic amines were associated with longer times for infants to become familiar with visual stimuli, suggesting poorer visual attention.
For every natural logarithmic unit increase in combined aromatic amine exposure, the time required to reach familiarisation increased by an estimated 7.1 units.
Similarly, exposure to 4,4′-methylenedianiline was associated with increased familiarisation time. However, both confidence intervals crossed zero, meaning these overall associations were not statistically conclusive.
Higher prenatal cotinine concentrations were also associated with reduced novelty preference, indicating potentially poorer recognition memory.
The researchers additionally observed evidence that some associations differed according to infant sex. Higher aniline exposure was linked to longer familiarisation times among female infants, although the interaction result was borderline (p=0.06).
The findings suggest that prenatal exposure to certain aromatic amines may be relevant to early cognitive development, extending existing concerns about these chemicals beyond their established toxicological properties.
However, the researchers emphasised several limitations. Exposure was measured using a single urine sample during mid-pregnancy, which may not accurately represent chemical exposure throughout gestation.
The cohort also included a relatively highly educated population, potentially limiting how broadly the findings can be generalised.
Furthermore, the observational study cannot establish that aromatic amines directly caused changes in infant cognition, and the clinical significance of the small differences observed remains uncertain.
The authors called for larger longitudinal studies incorporating repeated exposure measurements and longer-term developmental follow-up to clarify whether prenatal aromatic amine exposure influences childhood cognitive outcomes.
Reference
Eick SM et al. Prenatal exposure to aromatic amines and associations with infant cognition in the ECHO.CA.IL cohorts. J Expo Sci Environ Epidemiol. Published online 21 September 2026. doi: 10.1038/s41370-026-00905-3 .
Featured image: New Africa on Adobe Stock
Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.
