Mothers who work in jobs where they are frequently exposed to toxic chemicals or experience high stress appear to have higher odds of having a child with autism spectrum disorder (ASD).
Specifically, a team of American and Danish researchers found that the odds of having a child with ASD were increased for mothers who were employed at least one year before conception up to the child’s infancy in the military (59%), the judicial sector (59%) and ground transportation (24%).
In their study published online in the journal Occupational & Environmental Medicine, the researchers suggest that working in defence occupations may mean being exposed to multiple hazards, including lead from artillery handling and training exercises, exhaust fumes, and industrial solvents.
Similarly, mothers employed in ground transportation may be exposed to exhaust fumes and particulate matter, they theorised.
They also suggest that stress at work (as might be experienced by those in the judicial sector) may contribute to maternal fatigue and discomfort, and may adversely impact child neurodevelopment, e.g. through increased inflammation during pregnancy.
However, the study did not find any link between ASD and mothers working in agriculture, where they may have been exposed to pesticides.
While the study initially found an increased likelihood of ASD diagnosis related to maternal work in air transportation, chemical processing industries and cleaning services, these were not found to be significant after taking into account other potential contributing factors.
The researchers concluded: “Maternal occupations with frequent exposure to toxicants and combustion products, as well as high-stress occupations, could contribute to neurodevelopmental risk.”
They suggest that future studies should look into specific exposures to see which have the greatest impact on the likelihood of ASD in offspring.
The study analysed data from 1,702 children with ASD, who were born between 1973 and 2012 in Denmark.
The mothers’ employment histories were obtained from the Danish Pension Fund Registry and grouped into seven occupational categories. – The BMJ
