Original research findings published online in the journal Nature suggest that mothers who work in jobs where they are frequently exposed to toxic chemicals or experience high stress are more likely to have a child with autism spectrum disorder (ASD). Occupational and environmental medicine.
ASD is a lifelong neurodevelopmental condition characterized by impaired social communication and restricted or repetitive behavior.
Previous studies have shown a possible association between certain maternal occupations and ASD in the child, but their findings are inconsistent.
However, these previous studies used small study samples or relied on self-reported exposure data. They also did not evaluate the timing of occupational exposure during different developmental periods.
To overcome these limitations, researchers of the new study examined data on mothers’ occupations before conception, during pregnancy, and during infancy to examine any effects on the neurodevelopment of any offspring.
They obtained data from 1702 cases of autism spectrum disorder (ASD) in children born between 1973 and 2012 in Denmark. These cases were matched with 108532 controls based on sex and year of birth.
Mothers’ employment histories were obtained from the Danish Pension Fund Registry and grouped into seven occupational categories.
Seventy percent of ASD cases and controls were male and a large portion (46%) were born in the 1990s.
In their analysis, the researchers also took into account potential confounders, including the mothers’ age, history of neuropsychiatric disorders, whether they smoked during pregnancy, and socioeconomic status.
The study found that the likelihood of having a child with ASD was increased for mothers who were employed in ground transportation, public administration, and the military from conception until infancy.
The study found that working in military or defense occupations before or during pregnancy increased the chances of a child being diagnosed with ASD by 59%.
Mothers who worked in ground transportation, where they could be exposed to combustion products, were 24% more likely to have a child with ASD.
The study found that working in the justice sector before and during pregnancy increased the likelihood of their offspring having ASD by 59%.
Associations were observed for occupations one year before conception, during pregnancy, and during infancy, although associations became weaker during the child’s infancy.
The study found no association between ASD and mothers working in agriculture, where they may have been exposed to pesticides. The increased likelihood of an ASD diagnosis related to occupations such as air transportation, chemical processing industries, and cleaning services was not found to be significant after other factors were taken into account.
Researchers suggest that working in defense occupations may mean being exposed to a number of hazards, including lead from artillery handling and training exercises, exhaust fumes, and industrial solvents.
Similarly, mothers working in ground and air transportation may also be exposed to exhaust fumes and particulate matter, he theorized.
Researchers suggest that stress at work (similar to those working in the judicial sector) may also contribute to maternal fatigue and distress and may adversely affect the baby’s neural development, for example, through increased inflammation during pregnancy.
This is an observational study, and thus, no firm conclusions can be drawn about cause and effect. One limitation of the study was that occupations were based on industry categories and did not include detailed information on job titles or functions. The study results may not be generalizable to populations outside Denmark.
The researchers concluded, “Frequent exposure to toxins and combustion products as well as maternal occupations with high-stress occupations may contribute to neurodevelopmental risk.”
They suggest that future studies should examine specific risks singly and jointly to determine which have the greatest impact on the likelihood of ASD in offspring.
Source:
Journal Reference:
Dickerson, AS, and others. (2026). The relationship between maternal occupational history and autism spectrum disorder diagnosis in offspring in Denmark. Occupational and environmental medicine. doi:10.1136/OMED-2026-110912. https://oem.bmj.com/content/early/2026/05/05/oemed-2026-110912
