Exposure to Flame-retardant Chemicals During Pregnancy Associated with Differences in Child Growth Patterns

Authors: Anne P. Starling, Jessie P. Buckley, Deborah Bennett, 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. Pregnant women are commonly exposed to these chemicals. While prior studies have examined the effects of OPE exposure during pregnancy on birth outcomes, less is known about how prenatal exposure to these chemicals affects children’s growth patterns beyond infancy. Understanding how early-life environmental exposures are associated with child growth trajectories is important because childhood growth rates can be linked to later risk of obesity and heart disease. This study specifically examined the relationship between OPE exposure during pregnancy and child height, weight, and body mass index (BMI).

What were the study results?

The study found that exposure to specific OPEs during pregnancy was associated with differences in child growth rates between ages 2 and 10 years. Higher prenatal exposure to bis (1,3-dichloro-2-propyl) phosphate (BDCPP) was associated with faster increases in weight and height during early childhood (ages 2–5). In mid-childhood (ages 6–10), higher prenatal exposure to diphenyl phosphate (DPHP) was associated with faster increases in body mass index and weight. In contrast, prenatal exposure to bis(1-chloro-2-propyl) phosphate (BCPP) was associated with slower growth across multiple periods. Some associations differed by child sex and by maternal pre-pregnancy body mass index.

What was this study's impact?

These findings suggest that exposure to certain flame-retardant chemicals during pregnancy may be associated with children’s growth patterns. Because growth trajectories are linked to future obesity and metabolic health, these results underscore the importance of understanding and potentially reducing exposure to these widely used chemicals during pregnancy.

Who was involved?

The study included 4,566 mother-child pairs from 14 ECHO Cohort Study Sites across the United States. Researchers collected exposure data during pregnancy and collected growth data from ages 2 to 10 years.

What happened during the study?

Researchers measured nine chemical markers of OPE exposure in urine samples collected from pregnant participants. They later collected child weight and height measurements between ages 2 and 10 years, which were used to calculate each child’s BMI. The researchers then used statistical models to examine how prenatal OPE exposure was associated with rates of change in weight, height, and BMI.

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 biological mechanisms linking prenatal OPE exposure to child growth and examine whether reducing exposure during pregnancy could improve long-term child health outcomes. Additional studies may also explore the combined effects of multiple environmental chemical exposures during pregnancy and early childhood on the patterns of child growth patterns.

Where can I learn more?

Access the full journal article, titled “Gestational exposure to organophosphate ester flame retardants and child growth in weight, height, and body mass index at age 2-10 years: the Environmental influences on Child Health Outcomes Program” in Environmental Research.

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

Read the associated article.

Download this summary

Exposure to Flame-retardant Chemicals During Pregnancy Associated with Differences in Child Growth Patterns

Exposure to Flame-retardant Chemicals During Pregnancy Linked to Differences in Child Growth Patterns

Posted on April 8, 2026April 8, 2026 by Jodi Snare

Prenatal exposure to certain flame-retardant chemicals may be associated with differences in how children grow from early childhood through age 10, according to a recent ECHO Cohort study by Anne P. Starling, PhD, and Jessie P. Buckley, PhD, of UNC Chapel Hill, and Deborah Bennett, PhD, of University of California, Davis.

Organophosphate esters (OPEs) are widely used as flame retardants and plastic softeners in a variety of household and industrial products. Because these chemicals can be found in everyday environments, pregnant women are commonly exposed. While previous research has examined OPE exposure during pregnancy in relation to birth outcomes, less is known about whether prenatal exposure may be linked to children’s growth patterns beyond infancy.

To better understand these potential relationships, researchers measured nine chemical markers of OPE exposure in urine samples collected from pregnant participants. They then analyzed children’s weight and height measurements collected between ages 2 and 10 years and calculated body mass index (BMI). Using statistical models, the team examined whether prenatal OPE exposure was associated with differences in the rate of change in children’s weight, height, and BMI over time.

Researchers looked at 4,566 mother-child pairs from 14 ECHO Cohort Study Sites across the United States.

Key Takeaways :

Prenatal exposure to specific OPEs was associated with differences in child growth rates between ages 2 and 10.
Higher prenatal exposure to bis (1,3-dichloro-2-propyl) phosphate (BDCPP) was associated with faster increases in weight and height during early childhood (ages 2–5).
In mid-childhood (ages 6–10), higher prenatal exposure to diphenyl phosphate (DPHP) was associated with faster increases in BMI and weight.
Prenatal exposure to bis(1-chloro-2-propyl) phosphate (BCPP) was associated with slower growth across multiple periods.
Some associations differed by child sex and by maternal pre-pregnancy body mass index.

“This work increases our understanding of the potential long-term effects on child health from typical levels of exposure to these chemicals during pregnancy. The results may inform future guidance on the production and use of OPEs,” said Dr. Starling.

Additional research could help clarify the biological mechanisms involved and explore whether reducing exposure during pregnancy could support long-term child health.

This collaborative research, titled “Gestational exposure to organophosphate ester flame retardants and child growth in weight, height, and body mass index at age 2-10 years: the Environmental influences on Child Health Outcomes Program,” is published in Environmental Research.

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

Posted on February 3, 2026February 3, 2026 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

Read the associated article.

Download this summary

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

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

Posted on August 26, 2025August 26, 2025 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

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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

Read the related research alert.

Download this summary

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

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

Posted on July 18, 2025July 18, 2025 by Jodi Snare

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

Read the related research alert.

Download this summary

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