Pesticide gestational exposure may contribute to the development of allergies in childhood, yet evidence on its health impact on urban populations remains limited. This study investigates the association between prenatal exposure to individual and mixed pesticides and allergic outcomes, including asthma, wheezing, and eczema, at age 6 in 387 mother-child pairs from the LiNA cohort. Forty pesticides and metabolites were detected in urine during pregnancy through non-targeted screening, and 11 were selected (detection rate≥17%) for further analysis. Multivariable logistic regression models adjusted for covariates revealed statistically significant associations between dihydroxy-pyrimethanil and asthma (aOR=1.36, 95% CI: 1.04–1.80), and fluazifop-desbuthyl and wheezing (aOR=1.15, 95% CI: 1.01–1.31). No significant associations were observed for eczema. The mixture effect analysis with weighted quantile sum (WQS) regression showed that higher pesticide co-exposures significantly increased wheezing odds (aOR=2.08, 95% CI: 1.21–3.56). The main components of the WQS index were fluazifop-desbuthyl, flonicamid, hydroxy-metazachlor, and terbuthylazine, accounting for 67% of the overall dose-additive effect. These findings suggest that prenatal exposure to pesticides at dietary levels may increase the risk of childhood asthma and wheezing. Further epidemiological studies should replicate our findings by considering exposures to other pesticides of concern and their metabolites.

Synopsis Risk assessment of chemical mixtures should cover dietary exposure to non-persistent pesticides in urban populations by screening for compound-specific metabolites.

The authors have declared no competing interest.

This is a study from the ENDOMIX project: Understanding how endocrine disruptors and chemical mixtures of concern target the immune system to trigger or perpetuate disease. ENDOMIX has received funding from the European Union's European Health and Digital Executive Agency under grant agreement No. 101136566. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Health and Digital Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. The LiNA study was supported by intramural funding from the Department of Environmental Immunology at the Helmholtz Centre for Environmental Research (UFZ).

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The Lifestyle and environmental factors and their influence on the Newborn Allergy risk (LiNA) prospective birth cohort recruited 622 pregnant women between 2006 and 2008 in Leipzig, Germany, under the approval of the Review Board of Leipzig University (file No. 0462006). All participants signed the informed consent voluntarily.

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