chemical exposures

Prenatal Exposure to One Type of PFAS Linked to Small Differences in Children’s Sleep

Posted on by Jodi Snare

Children whose mothers had higher levels of one type of PFAS during pregnancy tended to have slightly more sleep problems between ages 1 and 5, according to a recent ECHO Cohort study led by Sarah D. Geiger, PhD, and Cai Zhang, of the University of Illinois Urbana-Champaign. 

Per- and polyfluoroalkyl substances, or PFAS, are long-lasting chemicals found in many consumer and industrial products. They can remain in the environment and in people’s bodies for a long time. During pregnancy, PFAS can cross the placenta, meaning a developing baby may be exposed before birth. 

Researchers studied 2,836 mother-child pairs from 14 ECHO Cohort study sites across the United States and Puerto Rico. They measured levels of four PFAS chemicals in blood samples collected during pregnancy. Caregivers later answered questions about their children’s sleep, including difficulty falling asleep, waking during the night, nightmares, and resistance at bedtime.  

Higher levels of perfluorooctanoic acid, or PFOA, during pregnancy were linked to slightly more sleep problems in young children. The pattern was similar in boys and girls. The other three PFAS chemicals studied were not clearly linked to children’s sleep problems. 

“Sleep is one of the most common concerns parents raise in early childhood, yet it is rarely studied as an outcome of prenatal chemical exposure,” said Zhang, a doctoral student at the University of Illinois Urbana-Champaign. “The difference for any one child was small, but exposure to these chemicals is widespread, so even small differences are worth continued study.” 

Future studies could examine whether prenatal PFAS exposure continues to relate to sleep as children grow older. Researchers could also study combinations of PFAS, newer replacement chemicals, and sleep measurements collected through wearable devices. 

This collaborative research, titled “Prenatal PFAS exposure and early childhood sleep quality in the ECHO Cohort,” is published in Environmental Research.  

Higher Blood Levels of Certain Metals During Pregnancy Associated with Autism-Related Traits in Children

Posted on by Jodi Snare

Pregnant woman

Higher levels of certain metals in mothers’ blood during pregnancy—including lead, mercury, and cadmium—were associated with autism-related traits in children, and higher levels of cadmium were associated with higher odds of an ASD diagnosis, according to a study funded by the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) Program.

Lead, mercury, and cadmium are metals that people may be exposed to through sources such as food, air, water, tobacco smoke, and some consumer products. During pregnancy, some metals can cross the placenta and reach the developing fetus. Previous studies have suggested possible links between prenatal metal exposure and ASD, but findings have been mixed, and many studies have examined one exposure at a time rather than the combined effects of multiple metals.

In this study, researchers analyzed data from mother-child pairs enrolled in the ECHO Cohort. They found that higher prenatal blood levels of lead and mercury were associated with higher scores on the Social Responsiveness Scale, Second Edition (SRS‑2), a caregiver-reported measure of social and behavioral traits related to autism. Higher blood cadmium levels were associated with higher odds of an ASD diagnosis.

When researchers looked at the metals together, higher combined levels of arsenic, cadmium, mercury, and lead were also associated with differences in autism-related behaviors, particularly in areas related to social functioning. Most metals measured in urine were not associated with these outcomes after accounting for other factors, although one metal (barium) showed differences by child sex that may warrant further study.

“We found that higher prenatal levels of metals—including lead, mercury, and cadmium—both individually and in combination, were associated with a higher likelihood of autism diagnosis and greater levels of autism-related behaviors, even at concentrations not typically considered elevated,” said Pi-I Debby Lin, ScD, of Harvard Pilgrim Health Care Institute. “These findings underscore the importance of increasing awareness of environmental exposures and strengthening approaches to screening during pregnancy, while continuing to evaluate what levels of exposure may be considered safe during this critical window of development.”

The study included 479 mother-child pairs with prenatal blood metal measurements and 482 pairs with prenatal urine metal measurements. Mothers provided samples during pregnancy, and researchers later compared those measurements with children’s SRS‑2 scores and ASD diagnoses when available. The analyses accounted for factors such as study site, maternal age, income, education, smoking exposure, and child sex.

The study, “Associations of prenatal metal exposures with autism-related outcomes in the ECHO Cohort,” was published in Environmental Epidemiology.

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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.