Prenatal Exposure to Certain Flame Retardants Associated with Autism-Related Traits, ECHO Study Finds

High exposure to some organophosphate esters (OPEs) during pregnancy was associated with higher scores for increased autism-related traits and greater odds of an autism diagnosis in children, according to research from the Environmental influences on Child Health Outcomes (ECHO) Program led by Jennifer Ames, PhD, and Lisa Croen, PhD of Kaiser Permanente Northern California. Overall, the study found generally small associations between three OPEs and child autism-related outcomes.

OPEs, often called “regrettable replacements,” replaced polybrominated diphenyl ethers (PBDEs) in the mid-2000s as flame retardants and plastic softeners, and are now found in furniture, electronics, construction materials, textiles, and infant products. Despite their widespread use, little is known about their effects on child development.

In this study, ECHO researchers analyzed urine samples from 4,159 pregnant mothers for nine OPE biomarkers and assessed children’s autism-related traits using the Social Responsiveness Scale (SRS), along with autism diagnoses.

Key findings include:

  • High exposure to bis(butoxyethyl) phosphate (BBOEP) was associated with higher autism-related trait scores and greater odds of an autism diagnosis, particularly among boys.
  • Bis(1-chloro-2-propyl) phosphate (BCPP) exposure was linked to higher autism-related trait scores.
  • High exposure to bis(2-chloroethyl) phosphate (BCETP) was associated with lower odds of an autism diagnosis.

“Organophosphate esters are widely used, but their potential effects on neurodevelopment are understudied. Our findings highlight the need for further research to understand their long-term effects on child neurodevelopment,” said Dr. Ames.

The study included children born from 2006 to 2020 at 15 ECHO Cohort sites across the United States.

This collaborative research, titled “Exposure to organophosphate ester flame retardants and plasticizers during pregnancy and autism-related outcomes in the ECHO Cohort,” is published in Environmental Health Perspectives.

Prenatal Exposure to Organophosphate Esters Associated with Increased Autism-Related Outcomes, ECHO Study Finds

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Prenatal Exposure to Organophosphate Esters Associated with Increased Autism-Related Outcomes, ECHO Study Finds

Author(s): Jennifer Ames, et al.

 

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

 

Why was this study needed?

Organophosphate esters (OPE) replaced harmful polybrominated diphenyl ethers (PBDEs) as flame retardants and plastic softeners in the mid-2000s. They are now present in various household and industrial products, including polyurethane foam, furniture, electronics, construction materials, infant products, textiles, and fabrics. Health officials and researchers currently know little about how OPEs affect child development. Earlier studies have suggested a link between prenatal exposure to these chemicals and birth outcomes and cognitive and behavioral problems in children. This study investigated the potential effects of prenatal exposure to nine OPEs on child autism-related outcomes.

 

What were the study results?

The study found generally small associations between three OPEs and child autism-related outcomes. Specifically, high exposure to bis(butoxyethyl) phosphate (BBOEP) was associated with higher scores for autism-related traits and greater odds of autism diagnosis. Another OPE, bis(1-chloro-2-propyl) phosphate (BCPP) showed associations with higher autism-related trait scores. High exposure to bis(2-chloroethyl) phosphate (BCETP) was associated with lower odds of autism diagnosis. The study also found that the association between BBOEP and higher autism-related traits scores was stronger in boys than in girls.

 

What was the study's impact?

This study underscores the need to better understand and address the potential developmental toxicity of these widely used chemicals.

 

Who was involved?

The study included 4,159 mother-child pairs with children born from 2006 to 2020 from 15 study sites in the ECHO Cohort.

 

What happened during the study?

Researchers analyzed urine samples from pregnant mothers for nine OPE biomarkers. The researchers then assessed child autism-related traits via the Social Responsiveness Scale (SRS) and collected information on whether they received a clinical autism diagnosis to examine associations between prenatal OPE exposure and child neurodevelopment.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What happens next?

Future research could replicate these findings in different populations and use multiple measures of OPEs throughout pregnancy to better understand the critical exposure windows and long-term effects of OPEs on child neurodevelopment. Additionally, further studies could help researchers explore the potential sex-specific effects of prenatal OPE exposure.

 

Where can I learn more?

Access the full journal article, titled “Exposure to organophosphate ester flame retardants and plasticizers during pregnancy and autism-related outcomes in the ECHO Cohort,” in Environmental Health Perspectives.

 

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published June 11, 2025

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