chemical exposures

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

Posted on 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 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

Pregnancy Stress Can Influence Relationship Between Chemical Exposures & Birth Outcomes, ECHO Study Finds

Posted on by Jodi Snare

Stress, anxiety, and depression during pregnancy and maternal adverse childhood experiences may influence the relationship between certain chemical exposures and birth outcomes, according to a new ECHO Cohort study led by Stephanie Eick, PhD, MPH and Anne Dunlop, MD, MPH of Emory University.

Most previous research on the effects of chemical exposures on birth outcomes has focused on a small number of well-established chemicals, such as bisphenol A (BPA) and certain phthalates. However, there are over 350,000 chemicals registered for global use, and the impact of many emerging or understudied chemicals on birth outcomes is not well understood. Additionally, prior studies have not adequately considered how different kinds of maternal stress (such as anxiety, depression, and adverse childhood experiences) might influence the effects of chemical exposures during pregnancy.

This study included 1,556 mother-child pairs from eleven ECHO Cohort Study Sites across the United States. Researchers analyzed urine samples from pregnant participants for 113 different chemicals from 10 chemical classes. Participants also reported on their stress, depression, anxiety, and adverse childhood experiences, allowing researchers to evaluate how these factors affect the relationship between different chemical exposures and birth outcomes.

Key Takeaways include:

  • Exposure to chemicals found in certain consumer and industrial products (such as phthalates, bisphenols, and insecticides) was associated with shorter pregnancies among women who experienced anxiety during pregnancy or in the early postpartum period.
  • Depression modified how exposure to certain chemicals (such as phthalates, parabens, and insecticides) affected birthweight and length of pregnancy.
  • Some chemicals positively correlated with length of pregnancy (duration) for mothers with more depression, while others were associated with lower birthweights when mothers had more depression symptoms.
  • The effects of a mother’s stress on the relationship between chemical exposures and birth outcomes depended on the type of chemical and type of stressor experienced.

“These findings suggest that screening for depression and anxiety during pregnancy could help identify women who may be at a higher risk of adverse birth outcomes,” said Dr. Eick.

Additional studies looking at the combined effects of multiple combined exposures could help researchers better understand the role of these factors in influencing birth outcomes. Future research could also further investigate potential biological effects of maternal adverse childhood experiences.

This collaborative research, titled “Psychosocial Stressors as Modifiers of the Associations Between Well-Studied and Understudied Chemicals and Birth Outcomes in the ECHO Cohort,” is published in Environmental Pollution.

Read the research summary.

PFAS Exposures During Pregnancy Not Significantly Associated with Child Behavior Issues

Posted on by Jodi Snare

Exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy was not significantly associated with behavior issues in children, according to a new ECHO Cohort study led by Catherine Bulka, PhD of the University of South Florida and Rebecca Fry, PhD of the University of North Carolina, Chapel Hill.

PFAS are man-made chemicals used in some consumer and industrial products like cookware, stain-resistant fabrics, and foams used to fight fires. They are often referred to as “forever chemicals” because they don’t break down easily, causing them to build up in water, soil, and air. Previous findings on the effects of prenatal PFAS exposure on child behavior have been inconclusive due to small sample sizes, limited exposure variability, and differing measures of child behavior. This study included children from nine ECHO Cohort study sites across the United States, including 1,723 preschool-age children (1.9-5.9 years) and 627 school-age children (6-15 years). Researchers measured mothers’ PFAS exposure through blood samples collected during pregnancy (between 2- and 42-weeks’ gestation) and assessed children’s behavior using the Child Behavior Checklist (CBCL).

Key Takeaways include:

  • Most of the PFAS detected in pregnant mothers were not clearly linked to behavior problems in their children overall.
  • Children whose mothers had medium levels of exposure to perfluorohexane sulfonate (PFHxS) during pregnancy showed more emotional problems, like being easily upset or withdrawn, especially when they were preschoolers. This pattern was not seen at very high or low levels of PFHxS exposure.
  • There were no strong connections between PFAS exposure before birth and behavior problems when the children were older (school-age).
  • Looking at combined exposures to multiple PFAS also did not show any clear relationship with child behavior.

“While most PFAS showed no association with behavioral problems, some suggestive, non-linear relationships emerged, indicating that these exposures may influence neurodevelopment in complex and unexpected ways,” said Dr. Bulka.

Additional studies could help researchers assess the effects of PFAS exposure during the postnatal period, which may be a more relevant window for childhood brain development and behavioral issues. Also, as some PFAS are being phased out of consumer products and replacements are emerging, future studies could help researchers understand the potential effects of exposures to these newer replacement chemicals.

This collaborative research, titled “Prenatal Exposure to Per- and Polyfluoroalkyl Substances: Association with Child Behavior in the Environmental influences on Child Health Outcomes (ECHO) Cohort,” is published in Environment International.

Read the research summary.

ECHO Participants and Investigators Featured in The Washington Post

Posted on by Jodi Snare

The Washington Post recently featured the Environmental influences on Child Health Outcomes (ECHO) Program in a story on phthalates—chemicals commonly found in plastics and personal care products—and how they may affect babies’ development during pregnancy.

The article highlighted ECHO participants who are helping researchers understand how chemical exposures during pregnancy and throughout the life course may influence pregnancy outcomes and child health. ECHO participants Arica Nyamsi and Cassondra Perez shared a range of experiences with chemical exposures, from making significant lifestyle changes to expressing uncertainty and a need for clearer guidance.

Sheela Sathyanarayana, a professor of pediatrics at the University of Washington, explained that determining safe levels of phthalate exposure is challenging because individual health risks vary based on genetics and susceptibility.

The story also featured ECHO investigator Dr. Leonardo Trasande of NYU Grossman School of Medicine, who noted in the article:

“Endocrine-disrupting chemicals are one of the biggest global health threats of our time. And 2 percent of us know about it — but 99 percent of us are affected by it.”

Chemical exposures will be a focus at the ECHO Symposium: Translating Science to Action on September 15, 2025. During the first session, Dr. Trasande will discuss phthalate exposure in pregnancy and early childhood, focusing on the evidence, knowledge gaps, and opportunities to inform policies, practices, and programs. Mrs. Perez will also speak during the third session on her experience as an ECHO participant.

Learn more about ECHO’s ongoing research on chemical exposures. Also, review the full symposium agenda for details and register to attend this free event either in-person or virtually.

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.

Prenatal Exposure to Phthalates, But Not Alternatives, May Influence Children’s Behavior, ECHO Study Finds

Posted on by Jodi Snare

Exposure to certain phthalates during pregnancy is associated with small to modest increases in behavioral issues, such as aggression and attention problems, in children aged 1.5 to 5 years, according to ECHO Cohort research led by Jiwon Oh, PhD and Deborah Bennett, PhD of the University of California Davis.

Researchers analyzed 27 phthalate and 6 alternative plasticizer metabolites in a large and diverse group of participants, exploring how these chemicals relate to both internalizing behaviors (like anxiety and depression) and externalizing behaviors (such as emotional reactivity, aggression, and attention difficulties).

The study found that higher levels of two specific phthalate metabolites—mono-benzyl phthalate (MBzP) and mono-hexyl phthalate (MHxP)—were connected to more externalizing behaviors, such as aggression or attention problems. However, these chemicals weren’t strongly linked to internalizing behaviors like anxiety or depression. The study also looked at a newer plasticizer called DINCH but didn’t find any effects on children’s behavior.

“While this study did not observe neurobehavioral impacts of the alternative plasticizer DINCH, a broader range of alternative plasticizers deserves attention due to their increasing use and potential neurotoxicity observed in laboratory studies,” said Jiwon Oh, PhD, of the University of California, Davis, who led the research.

The impact of these chemicals varied between boys and girls and depended on the neighborhood where the children lived. Some chemicals had stronger associations in kids from neighborhoods with more resources, while others were more impactful in areas with fewer resources.

These findings highlight the importance of understanding how prenatal exposure to widely used chemicals may affect early childhood behavior and underscore the need for further research on plasticizers that are used as replacements for phthalates.

This collaborative research titled “Prenatal exposure to phthalates and alternative plasticizers and emotional 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 Phenols During Pregnancy Associated with Changes in Non-nutritive Suck Patterns in Infants, an Early Indicator of Brain Development

Posted on by Jodi Snare

Exposure to phenols—chemicals used in a variety of consumer products and industrial processes that can disrupt hormones—during pregnancy was associated with changes in patterns of infant non-nutritive suck, according to ECHO Cohort research led by Megan Woodbury, PhD and Emily Zimmerman, PhD, CCC-SLP of Northeastern University, and Andréa Aguiar, PhD of University of Illinois Urbana-Champaign.

Non-nutritive sucking is a common behavior during infancy where a baby may suck on an object that cannot provide nutrients, such as a pacifier. Non-nutritive sucking is characterized by bursts of sucking separated by pauses to breathe. Researchers can measure the frequency, speed, and strength of non-nutritive sucking. Because sucking is a behavior present from birth that is controlled by neurons in the brainstem, it is an ideal indicator of early brain development.

During the study, researchers measured phenol exposure by analyzing phenol levels in maternal urine samples collected during pregnancy. Non-nutritive sucking was evaluated in 1- to 8-week-old infants using a custom pacifier for approximately 5 minutes.

Key takeaways include:

  • Exposure to Bisphenol F, a common alternative to Bisphenol A or BPA found in some food packaging, was related to a lower non-nutritive suck frequency.
  • Exposure to Triclosan, an antimicrobial chemical found in some soaps, was associated with a higher non-nutritive suck frequency.
  • Exposure to other phenols used as preservatives and industrial processes (propylparaben, 2,4-dichlorophenol, and 2,5-dichlorophenol) was associated with weaker non-nutritive suck.
  • Exposure to some phenols used in sunscreens and industrial processes (benzophenone-3, 2,4-dichlorophenol, and 2,5-dichlorophenol) was related to more non-nutritive suck bursts per minute.
  • Propylparaben, a chemical used in some preservatives, was associated with more non-nutritive sucking per burst.

Previous studies linking changes in non-nutritive suck patterns to other exposures, such as maternal pregnancy stress and prenatal phthalate exposures, have also linked these exposures with decreased cognitive function in infants. The reasons these associations occur in the body are unknown but may be linked to hormone disruption during pregnancy.

“This study provides additional evidence that exposure to phenols may be related to developmental outcomes in children, demonstrating the need for continued research into how exposures during pregnancy impact infant health and development,” said Dr. Woodbury.

This collaborative research, titled “Examining the association between prenatal Phenol exposure and infant non-nutritive suck in two ECHO Cohorts,” was published in Environmental Epidemiology.

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

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

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