Mothers who work in jobs where they are frequently exposed to toxic chemicals or experience high levels of stress are more likely to have children with autism spectrum disorder (ASD), suggests an original study published online in the journal Children’s Health. Occupational and environmental medicine.
ASD is a lifelong neurodevelopmental condition characterized by impairments in social communication and restricted or repetitive behaviors.
Previous research has shown a potential association between some maternal occupations and children’s ASD, but the results have been inconsistent.
However, these previous studies tended to use small study samples or rely on self-reported exposure data. They also did not assess the timing of occupational exposures at different developmental stages.
To overcome these limitations, researchers in the new study examined data on mothers’ occupations before, during pregnancy, and during infancy to investigate its effects on offspring’s neurodevelopment.
They obtained data on 1,702 cases of autism spectrum disorder (ASD) in children born between 1973 and 2012 in Denmark. These cases were matched to 108,532 controls based on gender and year of birth.
Mothers’ employment history was obtained from the Danish Pension Fund Register and categorized into seven occupational categories.
Seventy percent of the ASD cases and controls were male, and the majority (46%) were born in the 1990s.
The researchers also considered potential confounders in their analysis, including maternal age, history of neuropsychiatric disorders, whether or not they smoked during pregnancy, and socioeconomic status.
The study found that mothers who worked in land transportation, government, or the military before conception and during early childhood were more likely to have children with ASD.
The study found that working in a military or defense occupation before or during pregnancy increased the odds of a child being diagnosed with ASD by 59%.
Mothers who worked in land transportation jobs where they could be exposed to combustion products were 24% more likely to have a child with ASD.
And working in the justice sector before and during pregnancy increased the likelihood of offspring having ASD by 59%, the study found.
Associations were observed for occupations held in the year before pregnancy, during pregnancy, and during infancy, but the association weakened during the child’s infancy.
The study found no association between ASD and mothers working in agriculture, who may have been exposed to pesticides. The increased likelihood of an ASD diagnosis associated with occupations such as air transport, chemical processing industries, and janitorial services was found to be nonsignificant after accounting for other confounders.
Researchers suggest that working in defense jobs can expose you to multiple hazards, including lead, exhaust fumes, and industrial solvents from artillery handling and training.
Similarly, mothers working in ground and air transportation may be exposed to exhaust fumes and particulate matter, they theorized.
Researchers suggest that workplace stress (as well as the stress of working in the judicial field) may contribute to maternal fatigue and discomfort, and may have negative effects on children’s neurodevelopment, including through increased inflammation during pregnancy.
Because this is an observational study, no clear conclusions can be drawn about causality. A limitation of this study was that occupations were based on industry categories and did not include detailed information about job titles or duties. The study results may not be generalizable to people outside Denmark.
The researchers concluded that “maternal occupations with frequent exposure to toxic substances and combustion products and high-stress occupations may contribute to neurodevelopmental risk.”
They suggest that future studies should examine specific exposures, both singly and jointly, to investigate which have the greatest impact on the likelihood of ASD in offspring.
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Reference magazines:
Dickerson, Asphalt; others. (2026). Association between maternal occupational history and child autism spectrum disorder diagnosis in Denmark. Occupational and environmental medicine. DOI: 10.1136/oemed-2026-110912. https://oem.bmj.com/content/early/2026/05/05/oemed-2026-110912
