Occup Environ Med
Maternal job exposures linked to autism risk
Clinical Takeaway: Asking about maternal occupational history during preconception and prenatal care may help identify environmental risk factors worth flagging.
Maternal exposures during pregnancy have been linked to neurodevelopmental outcomes in children before, but prior work has often relied on small samples or pregnancy-only exposure data. This case-control study used Danish national registry data to look more systematically at which maternal occupations carry elevated odds, and when during the reproductive window those exposures matter.
Four occupational categories stood out after correction for multiple comparisons. Military and defense work carried the strongest signal, with a 59% increase in odds of an autism diagnosis in children. Judicial sector work (police, courts, corrections) showed a similar 59% increase overall, climbing to roughly double the odds when employment occurred during pregnancy specifically.
Ground transportation work was associated with a 24% increase, and public administration with a 20% increase. The patterns held for jobs held up to a year before conception and through pregnancy, with weaker signals during infancy.
Several occupations long suspected of carrying risk did not. Agriculture, with its presumed pesticide exposures, showed no association with autism odds. Air transportation, chemical processing, and cleaning services all showed initial signals that disappeared after statistical correction.
Associations were present for jobs held a year before conception, not just during pregnancy itself. The authors raise bioaccumulation as one possible explanation: some lipophilic compounds stored in adipose tissue can recirculate during pregnancy or lactation, meaning exposure to a mother years before conception could still reach the fetus.
Maternal work in ground transportation, air transportation, and the judicial sector raised autism risk in male children; public administration raised risk in female children. The authors propose that sex differences in placental function, hormonal pathways, and toxicant metabolism may underlie these patterns.
The study drew on 1,702 autism cases born in Denmark between 1973 and 2012, matched to 108,532 controls on sex and birth year, with maternal employment histories from the Danish Pension Fund Registry. The registry data captured industry categories rather than specific job tasks, so exposure within a category may vary substantially.
The authors frame the findings as a prompt for more targeted research rather than a basis for occupational counseling. Two common factors in the implicated occupations are combustion product exposure and high psychosocial stress, but the study cannot disentangle which contributes more, or whether the two interact.
"Maternal occupations with frequent exposure to toxicants and combustion products as well as high stress occupations could contribute to neurodevelopmental risk," the authors concluded.
Source: Dickerson AS. Occup Environ Med. 2026 May 12. Associations between maternal occupational history and autism spectrum disorder diagnosis in children in Denmark