organophosphate esters

Exposure to Certain Flame-Retardant Chemicals During Pregnancy Associated with Child Cognition

Posted on by Jodi Snare

Exposure to certain organophosphate esters (OPEs)—chemicals commonly used as flame retardants and plastic softeners in a variety of household and industrial products—during pregnancy was associated with slightly lower scores on tests of mental skills in young children, according to a new ECHO Cohort study led by Akhgar Ghassabian, MD, PhD of New York University Grossman School of Medicine.

Previous studies have suggested that OPEs may affect child brain development. With increasing human exposure to these chemicals, especially during sensitive periods like pregnancy, there has been concern about the potential impact on child cognitive development. This study included data from 831 mother-child pairs from three ECHO Cohort Study Sites in the United States. When pregnant women had higher urine levels of diphenyl phosphate (DPHP), a compound produced during the breakdown of certain OPEs in the human body, their children tended to have slightly lower scores on tests of mental skills at ages 4–6. This pattern was seen in boys and girls. Unexpectedly, boys whose mothers had higher levels of certain other chemicals linked to OPE exposure during pregnancy scored higher on these tests, but this was not true for girls.

“Results from this study suggest that OPE exposure during pregnancy may be associated with minor decreases in cognitive functioning in offspring,” said Dr. Ghassabian. “Considering that DPHP is a widely detected OPE metabolite in the U.S. population, the overall population impact of this modest effect size can be significant.”

Additional studies could help researchers better understand the biological pathways underlying these associations. Additional studies could also help clarify the association between some chemical markers of OPE exposure and higher cognitive scores among boys.

This collaborative research, titled “Prenatal exposure to organophosphate ester flame retardants and child cognition: findings from the Environmental influences on Child Health Outcomes cohort,” is published in Environmental Pollution. Read the research summary.

Exposure to Certain Flame-retardant Chemicals During Pregnancy May Be Linked with Decreased Cognitive Function in Young Children, ECHO Study Finds

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Exposure to Certain Flame-retardant Chemicals During Pregnancy May Be Linked with Decreased Cognitive Function in Young Children, ECHO Study Finds

Authors: Akhgar Ghassabian, 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 (OPEs) are chemicals widely used as flame retardants and plastic softeners in a variety of household and industrial products, and previous studies suggest they can affect child brain development. With increasing human exposure to these chemicals, especially during sensitive periods like pregnancy, there has been concern about the potential impact on child cognitive development. Previous studies have found mixed results, highlighting the need for a large, contemporary cohort study to clarify these associations and examine possible sex differences.

 

What were the study results?

When pregnant women had higher urine levels of diphenyl phosphate (DPHP), a compound produced during the breakdown of certain OPEs in the human body, their children tended to have slightly lower scores on tests of mental skills at ages 4–6. This pattern was seen in boys and girls. Boys whose mothers had higher levels of certain other chemicals linked to OPE exposure during pregnancy scored higher on these tests, but this was not true for girls. This finding was unexpected, so more research may be needed to understand the biological mechanism underlying this association.

 

What was this study's impact?

Results from this large contemporary cohort of mother–child pairs in the U.S. suggest that OPE exposure during pregnancy may be associated with minor decreases in cognitive functioning in children. Considering that DPHP is a widely detected marker of OPE exposure in the U.S. population, the overall impact of this effect may be significant.

 

Who was involved?

The study included 831 mother–child pairs from three ECHO Cohort Study Sites in the United States.  The study population was predominantly non-Hispanic White and highly educated, which may limit generalizability.

 

What happened during the study?

Pregnant participants provided urine samples for measurement of nine OPE chemicals. Researchers assessed child mental skills using standardized intelligence scales when children were between 4 and 6 years old. Researchers then used statistical analyses to examine associations between OPE exposure and childhood cognition.

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?

Additional studies could help researchers better understand the biological pathways underlying these associations. Additional studies could also help clarify the association between some chemical markers of OPE exposure and higher cognitive scores among boys.

 

Where can I learn more?

Access the full journal article, titled “Prenatal exposure to organophosphate ester flame retardants and child cognition: findings from the environmental influences on child health outcomes cohort,” in Environmental Pollution.

 

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

 

Published February 1, 2026

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Exposure to Certain Flame-retardant Chemicals During Pregnancy May Be Linked with Decreased Cognitive Function in Young Children, ECHO Study Finds

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Neurodevelopment

Exposure to Certain Flame-retardant Chemicals During Pregnancy May Be Associated with Behavioral Issues in Young Children

Posted on by Jodi Snare

Exposure to certain organophosphate esters (OPEs)—chemicals commonly used as flame retardants and plastic softeners in a variety of household and industrial products—during pregnancy was associated with more behavioral issues in young children, according to a new ECHO Cohort study led by Jiwon Oh, PhD and Deborah Bennett, PhD of the University of California, Davis.

Previous research has linked exposure to OPEs during pregnancy with potential adverse effects on child brain development, but more evidence is needed. In this study, researchers investigated the association between prenatal exposure to OPEs and child behaviors. The study included 2,948 mother-child pairs from 12 ECHO Cohort study sites across the U.S., and the investigators used the Child Behavior Checklist for ages 1½–5 to assess each child’s behavior during early childhood.

Among the nine OPEs measured, diphenyl phosphate (DPHP) was detected in almost all pregnant women (99.5%) and had the highest median concentration.  Other frequently detected OPEs included dibutyl phosphate/di-isobutyl phosphate (DBUP/DIBP), bis (1,3-dichloro-2-propyl) phosphate (BDCPP), bis(2-chloroethyl) phosphate (BCETP), bis(2-butoxyethyl) phosphate (BBOEP), and bis(1-chloro-2-propyl) phosphate (BCPP).

“This research builds on a growing body of evidence of potential harm caused by exposures to OPEs,” said Dr. Bennett.

Key Takeaways include:

  • Prenatal exposure to BBOEP (at moderate concentrations rather than high concentrations) was associated with more internalizing behaviors (e.g., anxiety, depression), externalizing behaviors (e.g., aggression, hyperactivity), and total behavior issues in young children.
  • Exposure to BCPP was associated with more externalizing behaviors and total behavior issues.
  • Detectable dipropyl phosphate (DPRP) was associated with fewer externalizing behaviors.
  • Boys showed more behavior issues associated with prenatal BDCPP and BCPP exposure.
  • Children from highly vulnerable neighborhoods—defined by community-level demographics, socioeconomic status, housing, access to transportation, and other factors—exhibited more behavior issues associated with prenatal BCPP exposure.

“While further research is needed, our findings suggest that reducing exposure to this chemical class during pregnancy may help mitigate emotional and behavioral problems in young children,” said Dr. Oh.

This collaborative research, titled “Prenatal Exposure to Organophosphate Ester Flame Retardants and Behavioral Outcomes in Early Childhood in the Environmental influences on Child Health Outcomes (ECHO) Cohort,” is published in Environment International.

Read the research summary.

Exposure to Common Flame-retardant Chemicals During Pregnancy May Be Associated with Behavioral Issues in Young Children, ECHO Study Finds

<< Back to Research Summaries

Exposure to Common Flame-retardant Chemicals During Pregnancy May Be Associated with Behavioral Issues in Young Children, ECHO Study Finds

Author(s): Jiwon Oh, 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 (OPEs) are chemicals commonly used as flame retardants and plastic softeners in a variety of household and industrial products, including furniture, electronics, infant products, and fabrics. Previous research has linked exposure to OPEs during pregnancy with potential adverse effects on child brain development, but more evidence is needed. In this study, researchers investigated the association between prenatal exposure to OPEs and child behaviors.

 

What were the study results?

Among the nine OPEs measured, diphenyl phosphate (DPHP) was detected in almost all pregnant women (99.5%) and had the highest median concentration. Other frequently detected OPEs included dibutyl phosphate/di-isobutyl phosphate (DBUP/DIBP), bis (1,3-dichloro-2-propyl) phosphate (BDCPP), bis(2-chloroethyl) phosphate (BCETP), bis(2-butoxyethyl) phosphate (BBOEP), and bis(1-chloro-2-propyl) phosphate (BCPP).

Prenatal exposure to BBOEP (at moderate concentrations rather than high concentrations) was associated with more internalizing behaviors (e.g., anxiety, depression, emotional reactivity), externalizing behaviors (e.g., aggression, inattention), and total behavior issues in young children. Exposure to BCPP was associated with more externalizing behaviors and total behavior issues. In contrast, detectable dipropyl phosphate (DPRP) was associated with slightly  fewer externalizing behaviors. Boys showed more behavior issues associated with prenatal BDCPP and BCPP exposure. Children from highly vulnerable neighborhoods—defined by community-level demographics, socioeconomic status, housing, access to transportation, and other factors—exhibited more behavior issues associated with prenatal BCPP exposure.

 

What was the study's impact?

Use of OPEs is increasing, with widespread exposure observed in pregnant women. While further research is needed, this study suggests that reducing exposure to certain chemicals during pregnancy may help mitigate emotional and behavioral problems in young children.

 

Who was involved?

The study included 2,948 mother–child pairs from 12 ECHO Cohort study sites across the United States. Non-Hispanic White (40.2%), non-Hispanic Black (28.6%), and Hispanic (21.3%) mothers were included in the study. Most participating mothers (85.2%) did not experience major pregnancy complications and most of their children (93.2%) were born after at least 37 weeks of pregnancy.

 

What happened during the study?

During the study, researchers collected urine samples from pregnant participants and analyzed them for nine chemical markers of OPE exposure. Later, researchers assessed the child’s behaviors using the Child Behavior Checklist for Ages 1½–5. The researchers then used statistical methods to examine associations between each OPE exposure during pregnancy and behavioral issues in children. The study also evaluated how other factors, like the child’s sex and their social vulnerability, may have influenced the effect of prenatal OPE exposure on their behavior.

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 studies could help researchers better understand the effects of prenatal OPE exposure on child brain development and determine whether reducing these exposures could be beneficial to children’s health and development.

 

Where can I learn more?

Access the full journal article, titled “Prenatal Exposure to Organophosphate Ester Flame Retardants and Behavioral Outcomes in Early Childhood in the Environmental influences on Child Health Outcomes (ECHO) Cohort,” in Environment International.

 

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

Published August, 2025

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Exposure to Common Flame-retardant Chemicals During Pregnancy May Be Associated with Behavioral Issues in Young Children, ECHO Study Finds

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NIH Study Finds Exposure to Flame-Retardant Chemicals During Pregnancy Was Associated with Varying Childhood Obesity Risks

Posted on by Jodi Snare

FOR IMMEDIATE RELEASE

 

Study reveals a complex link between pregnancy exposure to common chemicals and childhood obesity, researchers say.

Exposure to organophosphate esters (OPEs)—chemicals found in everyday products that use plastics and flame retardants—during pregnancy may have varying effects on the risks of childhood obesity, according to a new study funded by the Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health.

The study found that children aged 5 to 10 years who were exposed to higher levels of dibutyl phosphate and di-isobutyl phosphate (DBUP/DIBP) during pregnancy had a 14% greater risk of developing obesity compared to those with the lowest exposure levels. In contrast, children whose mothers had higher exposure levels of bis (1,3-dichloro-2-propyl) phosphate (BDCPP) during pregnancy had a 15% lower risk of developing obesity than those with the lowest levels of exposure.

“We are just beginning to understand how OPE exposure might be connected to obesity. Our findings suggest that the relationship between OPE exposure during pregnancy and childhood obesity is complicated, and more research is needed to look at a wider range of OPE chemicals,” said Assiamira Ferrara, MD, PhD, senior research scientist at Kaiser Permanente Northern California Division of Research.

These chemicals are OPEs, which replaced polybrominated diphenyl ethers (PBDE) as flame retardants and plastic softeners in the mid-2000s. Studies in toxicology and epidemiology suggest that these substances can interfere with hormone systems and may be linked to obesity.

The study involved 5,087 mother-child pairs from 14 ECHO Cohort Study Sites. Researchers measured the levels of OPEs in the mother's urine during pregnancy and their children's body mass index (BMI) during infancy up to age 10. The participants were pregnant between 2006 and 2020 when OPEs were being rolled out to replace PBDEs.

“These findings underscore the need for further research to inform public health programs and regulatory policies aimed at mitigating childhood obesity risks from environmental chemical exposures,” said Alicia K. Peterson, PhD staff scientist at Kaiser Permanente Northern California Division of Research.

Researchers across the ECHO Cohort reviewed and analyzed data for this study. This collaborative research  was published in Environment International.

Peterson, AK, et al. “Gestational Exposure to Organophosphate Ester Flame Retardants and Risk of Childhood Obesity in the Environmental influences on Child Health Outcomes.” Environment International. DOI: 10.1016/j.envint.2024.109071.

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About ECHO: Launched in 2016, the Environmental influences on Child Health Outcomes (ECHO) Program is a research program in the Office of the Director at the NIH with the mission to enhance the health of children for generations to come. ECHO investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

About the NIH: NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information, visit www.nih.gov.

 

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ECHO Study Investigates Exposure to Flame-Retardants During Pregnancy and Childhood Obesity Risk

ECHO Study Investigates Exposure to Flame-Retardants During Pregnancy and Childhood Obesity Risk

Authors: Alicia K. Peterson, Assiamira Ferrara, 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 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 have raised concerns about their impact on hormone systems and potential links to obesity. This study looked at whether the levels of OPEs found in a mother's urine during pregnancy were associated with a higher risk of obesity in her child.

 

What were the study results?

The study found varying associations between gestational OPE exposure and childhood obesity.  The study found that children aged 5 to 10 years who were exposed to higher levels of dibutyl phosphate and di-isobutyl phosphate (DBUP/DIBP) during their mother’s pregnancy had a 14% greater risk of developing obesity compared to those with the lowest exposure levels. In contrast, children whose mothers had higher exposure levels of bis (1,3-dichloro-2-propyl) phosphate (BDCPP) during their mother’s pregnancy had a 15% lower risk of developing obesity than those with the lowest levels of exposure. Researchers measured for evidence of nine different OPEs in pregnant participants’ urine. Evidence of exposure to DBUP/DIBP and BDCPP was present in more than 80% of the samples. No association with obesity risk was observed for the rest of the OPEs measured.

 

What was this study's impact?

The study highlights the potential public health issue of gestational OPE exposure and its association with childhood obesity. It suggests the need for further investigation across a broad range of OPE exposures and could inform potential regulations on the manufacture and use of OPEs.

 

Who was involved?

The study involved 5,087 individuals from 14 ECHO Cohort Study Sites. The study population was geographically, racially, and ethnically diverse.

 

What happened during the study?

Researchers measured OPE exposure in the urine samples of pregnant participants between 2006 and 2020 and collected BMI measurements for the children from infancy to age 10 years.

Note: 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?

Further studies could help researchers better understand the associations between gestational exposure across a broad range of OPE exposures and childhood obesity.

 

Where can I learn more?

Access the full journal article, “Gestational Exposure to Organophosphate Ester Flame Retardants and Risk of Childhood Obesity in the Environmental influences on Child Health Outcomes Consortium,” in Environment International.

 

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

 

Published October 17, 2024

 

Read the associated press release.

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ECHO Study Investigates Exposure to Flame-Retardants During Pregnancy and Childhood Obesity Risk

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