Does exposure to pesticides during pregnancy raise autism risk? Research points to possible links, especially with certain pesticides like organophosphates, but the evidence is not fully settled and calls for more study.
Pregnant women and their developing babies can come into contact with pesticides through food, home use, or farm work. These chemicals are designed to kill bugs, but they might affect human brains too. A key study looked at chlorpyrifos, a common organophosphate pesticide. Kids exposed to it before birth showed changes in brain structure, like unusual growth in parts of the brain surface. These kids were between ages 6 and 11, and the exposure came from normal home use, not heavy farm work. The study found ties to lower IQ and attention issues, which sometimes overlap with autism traits.
Other organophosphate pesticides have similar red flags. Research links prenatal exposure to smaller head size at birth, low birth weight, odd reflexes in newborns, and mental delays that look like early signs of developmental disorders. Three separate studies confirmed lower IQ in kids from both city and farm families, using tests on urine and cord blood to measure exposure. Even though home use of chlorpyrifos was banned in the US in 2001, farm spraying continues, and pesticide traces linger on produce.
Not all studies agree on autism itself. Some check pesticide exposure before pregnancy and find risks for birth problems like low implantation rates in fertility treatments or stillbirths, but results vary. One review of parent exposures noted higher odds of childhood brain tumors, but autism links are less direct. Broader data ties pesticides, along with air pollution and metals, to higher autism spectrum disorder rates in population studies.
Brain growth happens fast in the womb, making it sensitive to toxins. Pesticides might disrupt nerve cell growth or gene activity linked to autism. Still, factors like genes and other exposures play roles too. Experts worry about everyday contact through diet or home cleaning, even at low levels.
Sources:
https://www.pnas.org/doi/10.1073/pnas.1203396109
https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2025.1633266/full
https://www.ehn.org/wireless-radiation-autism-related-genes
https://dpcpsi.nih.gov/autism-data-science-initiative/funded-research
