Serious researchers have been able to correlate fetal exposure to chemical compounds called organochlorine chemicals with an 80 percent increase in a future autism diagnosis. Kristen Lyall, ScD, is an assistant professor in Drexel University’s A.J. Drexel Autism Institute.
Although production of organochlorine chemicals was banned in the United States in 1977, these compounds can remain in the environment and become absorbed in the fat of animals that humans eat, leading to exposure.
"There's a fair amount of research examining exposure to these chemicals during pregnancy in association with other outcomes, like birth weight -- but little research on autism, specifically," Lyall said. "To examine the role of environmental exposures in risk of autism, it is important that samples are collected during time frames with evidence for susceptibility for autism -- termed 'critical windows' in neurodevelopment. Fetal development is one of those critical windows."
Researchers and scientists from California’s Department of Public Health, members of Kaiser Permanente’s Division of Research and numerous others have released a paper—“Polychlorinated Biphenyl and Organochlorine Pesticide Concentrations in Maternal Mid-Pregnancy Serum Samples: Association with Autism Spectrum Disorder and Intellectual Disability”—describing their findings.
The team looked at a population sample of 1,144 children born in Southern California between 2000 and 2003. Data was accrued from mothers who had enrolled in California's Expanded Alphafetoprotein Prenatal Screening Program, which is dedicated to detecting birth defects during pregnancy.
Participants' children were separated into three groups: 545 who were diagnosed with autism spectrum disorder, 181 with intellectual disabilities but no autism diagnosis, and 418 with a diagnosis of neither.
Blood tests taken during the second trimester were used to determine the levels of exposure. There are tons of chemicals detectable in our bodies from exposure—including two different organochlorine classified chemicals, PCBs and OCPs. Lyall and others were interested in the “levels” of this exposure.