phthalates

ECHO Study Links Prenatal Exposure to Phthalate Replacement with Differences in Fetal Growth

Posted on by Jodi Snare

Higher prenatal exposure to a chemical increasingly used to replace phthalates was associated with differences in fetal growth, according to a recent ECHO Cohort study led by Leonardo Trasande, MD, MPP of NYU Langone Health.

Phthalates are widely used in food packaging, flooring, cosmetics, personal care products, and other everyday items. As manufacturers replace them with alternatives such as di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), researchers are working to understand whether these newer chemicals may also affect maternal and child health.

ECHO researchers analyzed data from 6,617 pregnancies at 22 ECHO Cohort Study Sites. They measured three DINCH breakdown products in urine collected during pregnancy and compared exposure levels with birth weight, birth length, pregnancy length, and infant size for gestational age.

Higher levels of DINCH-related markers were associated with lower birth weight and a greater likelihood of being born small for gestational age. Associations varied by infant sex: links with birth length were stronger among boys, while links with small-for-gestational-age status were stronger among girls. Third-trimester exposure appeared more strongly associated with lower birth weight for gestational age than exposure earlier in pregnancy.

Measurable DINCH markers were common among participants, suggesting widespread exposure in this population.

Because this was an observational study, the findings cannot show that DINCH directly caused these outcomes. Additional research may help clarify how DINCH affects pregnancy and fetal development and inform evaluations of other phthalate replacements.

This collaborative research, titled “Prenatal exposure to di(isononyl) cyclohexane-1,2-dicarboxylate and adverse birth outcomes in the USA: a prospective analysis of births in a large American birth cohort,” is published in Environment International.

Following U.S. Dietary Guidelines During Pregnancy May Be Linked to Differences in Chemical Exposure

<< Back to Research Summaries

Following U.S. Dietary Guidelines During Pregnancy May Be Linked to Differences in Chemical Exposure

Authors: Diana C. Pacyga, Jessie Buckley, 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?

Certain chemicals can end up in food during farming, processing, packaging, storage, or cooking. During pregnancy, some of these chemicals can get into the body through food. In a recent study, ECHO researchers detected, on average, 45 of the 113 chemicals studied in urine samples collected from pregnant participants. However, the U.S. Dietary Guidelines for Americans do not take chemical exposures into account. These chemicals may interfere with how the body’s systems work and could pose a risk for mothers and children. ECHO researchers wanted to know whether following these dietary guidelines closely during pregnancy was linked to lower exposure to chemicals. They also wanted to identify which parts of the diet were most closely related to chemical exposures.

 

What were the study results?

A diet during pregnancy that more closely followed U.S. Dietary Guidelines for Americans—such as eating more fruits, vegetables, whole grains, and lean proteins—was associated with differences in exposure to several types of chemicals when compared to those who didn’t follow the guidelines as closely.

In this study, following the dietary guidelines was generally associated with lower levels of some chemicals commonly found in food packaging, cooking byproducts, and the environment. For example, levels of one chemical (phthalate) that can leach into food from plastic packaging were about 13% lower among participants who closely followed the dietary guidelines. Eating more lean protein was the biggest factor related to lower levels of most chemicals.

However, following the guidelines was not linked to lower exposure to all chemicals. Participants whose diets more closely followed the dietary guidelines also had higher levels of some pesticides, food preservatives, and chemicals used in personal care products. For example, levels of one pesticide were 9% higher among participants who closely followed the guidelines and eating more fruits and vegetables and less added sugar were the main food components contributing to higher levels.

 

What was this study's impact?

This study suggests that following the U.S. Dietary Guidelines for Americans during pregnancy may help reduce exposure to many chemicals but could increase exposure to others. The results highlight areas where consumers could benefit from additional guidance to help reduce their dietary chemical exposures. For example, while fresh fruits and vegetables are an important part of a balanced diet during pregnancy, they can also be a source of pesticide exposure. The researchers suggested choosing organic when possible and washing or peeling produce to help reduce pesticide exposure to continue eating these healthy foods. These findings could help researchers and health experts think about how future revisions to dietary guidance might support nutrition while also helping to lower chemical exposure during pregnancy.

 

Who was involved?

The study included 1,492 pregnant participants from six ECHO Cohort Study Sites in California, Illinois, Michigan, Tennessee, and Georgia.

 

What happened during the study?

Participants completed a food questionnaire or survey about what they ate around the middle of pregnancy. Researchers used this information to calculate how closely each person’s diet matched the U.S. Dietary Guidelines for Americans, which is measured by the Healthy Eating Index. They also measured 113 chemicals in urine samples collected during pregnancy, covering 10 different classes of chemicals. Then they used statistical analyses to examine how diet quality was related to levels of chemicals in the body.

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 help identify practical ways to reduce chemical exposures through diet during pregnancy without lowering nutritional quality. The results may also help inform future updates to dietary recommendations and broader efforts to reduce chemicals in the food supply.

 

Where can I learn more?

Access the full journal article, titled “Dietary guidelines adherence and pregnancy exposure to 10 classes of priority chemicals: An observational study in the ECHO Cohort,” published in the American Journal of Clinical Nutrition.

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

 

Published July 8, 2026

Read the associated news release.

Download this summary

Following U.S. Dietary Guidelines During Pregnancy May Be Linked to Differences in Chemical Exposure

Read More Related Research Summaries

Pre-, Peri-, and Postnatal

A Healthy Diet During Pregnancy Associated with Lower Exposure to Some—But Not All—Chemicals, NIH Study Finds

Posted on by Jodi Snare

Young mother eating and reading book at home

Following dietary guidelines during pregnancy may reduce exposure to many —but not all— environmental chemicals from food and everyday products, according to a new study of nearly 1,500 pregnant participants funded by the Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health (NIH).

Diet is one way people can be exposed to environmental chemicals. These chemicals can enter foods during farming, processing, packaging, storage, or cooking. Understanding whether following current dietary recommendations that support a healthy pregnancy could also influence chemical exposures was a key question for ECHO researchers Diana Pacyga, PhD, MS and Jessie Buckley, PhD, MPH of the University of North Carolina Gillings School of Global Public Health.

Recent ECHO research found that pregnant participants were exposed to an average of 45 different environmental chemicals, highlighting the importance of understanding whether healthy eating patterns are linked to differences in exposures. “Lowering exposure to chemicals is particularly important during pregnancy, as earlier ECHO studies have also linked certain chemicals to worse health in mothers and their children” said Dr. Buckley.

Researchers examined diet and chemical exposures in nearly 1,500 pregnant participants in the ECHO Cohort, measuring more than 100 chemicals in urine samples and relating them to diet quality based on how closely participants followed the U.S. Dietary Guidelines for Americans.

Pregnant people whose diets more closely followed the guidelines, including eating more lean protein, had lower levels of some commonly encountered chemicals found in food packaging or formed as byproducts during cooking. For example, levels of one phthalate that can leach into food from plastic packaging were about 13% lower among participants with higher quality diets.

“What we discovered is that following the U.S. Dietary Guidelines may have two benefits—helping meet pregnancy nutrient needs and offering a way to reduce exposure to many common industrial chemicals,” said Dr. Pacyga.

However, the same dietary pattern does not lower exposure to all chemicals. Participants following the guidelines also had higher levels of certain chemicals. Notably, eating more fruits and vegetables and less added sugar were linked with higher levels of some pesticides, which can be found on fresh produce.

Overall, a diet higher in fruits, vegetables, whole grains, and lean proteins and lower in added sugar was linked with lower or higher exposure to different environmental chemicals, underscoring the complex relationship between food and chemical exposures. These findings highlight areas where consumers may benefit from additional guidance to help reduce their dietary chemical exposures.

“Fresh fruits and vegetables are important for a healthy pregnancy diet, but they can also be a source of pesticides,” Dr. Pacyga explained. “Buying organic, when possible, and washing or peeling produce may help reduce exposure while still eating these healthy foods.”

The researchers emphasize that following dietary guidelines remains an important part of a healthy pregnancy, but their findings could help inform future discussions about how dietary guidance addresses environmental exposures.

“A modest revision of the dietary guidelines to include advice on reducing chemical exposures could help protect pregnant women’s health without changing the food recommendations we already know support good nutrition,” Dr. Buckley said.

The researchers note that more studies are needed to better understand these relationships and to identify other practical ways to reduce exposure through diet.

The study, titled “Dietary guidelines adherence and pregnancy exposure to 10 classes of priority chemicals: An observational study in the ECHO Cohort,” was published in the American Journal of Clinical Nutrition.

About ECHO
The ECHO Cohort Consortium is a research program supported by the National Institutes of Health (NIH) with the mission to enhance the health of children for generations to come. ECHO Cohort investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

Media Contacts

For information or to request an interview, contact the ECHO Program Coordinating Center echocc@dm.duke.edu.

If you are not a member of the media, but have a general inquiry, please contact  NIHKidsandEnvironment@od.nih.gov.

Connect With Us

echo connector

Check out the recent issues of our bi-monthly newsletter, the ECHO Connector, for program news and the latest research findings.

To receive the ECHO Connector through email, subscribe here.

Follow the ECHO Program on LinkedIn and X for the latest updates.

Exposure to Multiple Chemicals During Pregnancy Linked to Associated with Adverse Birth Outcomes

Posted on by Jodi Snare

Exposure to certain chemicals during pregnancy was linked to differences in gestational age and birthweight, highlighting the need to better understand the potential health effects of both well-known and less-studied chemical exposures, according to a recent ECHO Cohort study led by Jessie Buckley, PhD, MPH of UNC Chapel Hill and Tracey Woodruff, PhD, MPH of Stanford University.

Pregnant women in the United States may be exposed to dozens of chemicals at the same time, including some that are not well understood.

“We found exposures to several newer chemicals that have been used to replace toxic ones. These chemicals are not well-studied but we found that they can have similar health effects as the chemicals they replace,” said Dr. Woodruff. “This finding underscores the need to better track and evaluate new chemicals before they are introduced.”

Researchers analyzed urine samples collected from pregnant participants and detected an average of 45 chemicals out of 113 measured. The study focused on whether higher levels of these chemicals were associated with differences in birth outcomes, including gestational age, birthweight adjusted for gestational age, and risk of preterm birth or being born smaller than expected.

Key findings include:

  • Exposure to several types of chemicals was associated with differences in birth outcomes.
  • Certain phthalates (used in plastics) and polycyclic aromatic hydrocarbons (found in air pollution and some foods) were linked to shorter pregnancies or lower birthweight for gestational age.
  • Some less-studied chemicals, such as halogenated phenols, were also associated with lower birthweight for gestational age.
  • In contrast, higher levels of some insecticides and benzophenones were associated with longer gestational age or higher birthweight for gestational age.

The study included 5,318 mother–child pairs from 18 ECHO Cohort sites across the United States, with participants enrolled between 2000 and 2021. Researchers accounted for factors that can influence birth outcomes—such as maternal age, education, and tobacco use during pregnancy—to better isolate the associations between chemical exposure and outcomes.

While the observed differences in birth outcomes were small, the findings underscore how widespread chemical exposures are during pregnancy and the importance of continuing to evaluate their potential health effects.

“Our findings add to existing evidence that chemical exposures during pregnancy can worsen birth outcomes, highlighting the importance of reducing toxic chemical exposures during early life,” said Dr. Buckley.

Future research could explore whether these exposures are also linked to other child health outcomes, such as neurodevelopment, obesity, or asthma.

This collaborative research, titled “Gestational exposure to ten classes of priority chemicals and birth outcomes in the ECHO Cohort,” was published in JAMA Network Open.

Exposure to Multiple Chemicals During Pregnancy Associated with Adverse Birth Outcomes

<< Back to Research Summaries

Exposure to Multiple Chemicals During Pregnancy Associated with Adverse Birth Outcomes

Authors: Jessie Buckley, Tracey Woodruff, 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?

Pregnant women in the United States are regularly exposed to many chemicals through food, water, air, dust, and consumer and personal care products. While some chemicals are known to affect pregnancy outcomes, many widely used chemicals are not well-studied, including replacement chemicals used as alternatives to other potentially harmful chemicals. ECHO researchers wanted to better understand the degree of chemical exposure during pregnancy and whether these exposures are linked to differences in the length of pregnancy or birthweight for gestational age.

 

What were the study results?

On average, researchers detected 45 of the 113 chemicals studied in urine samples collected from pregnant participants. Exposures to certain types of chemicals during pregnancy were linked to differences in adverse birth outcomes. Certain phthalates (used in plastics) and polycyclic aromatic hydrocarbons (found in air pollution and some foods) were linked to shorter pregnancies or lower birthweight for gestational age.

Some understudied chemicals, including halogenated phenols which can be found in antibacterial products such as soaps and antiseptics, were also associated with lower birthweight for gestational age. Urinary concentrations of certain insecticides and benzophenones often found in sunscreen, laundry, and cleaning products were associated with longer gestational age at birth or higher birthweight.

 

What was this study's impact?

The study highlights the importance of understanding the health effects of newer or less well-understood chemicals that may be replacing older ones on pregnancy and child health. The findings underscore how widespread chemical exposures are during pregnancy and the importance of continuing to evaluate their potential health effects.

 

Who was involved?

The study included 5,318 mother–child pairs from 18 ECHO Cohort sites across the United States. Participants were enrolled between 2000 and 2021, and all pregnancies included were single births.

 

What happened during the study?

Researchers collected a urine sample during mid-pregnancy (around 25 weeks) and measured 113 chemical analytes from 10 classes of chemicals. They examined whether higher levels of these chemicals were associated with pregnancy length, birthweight adjusted for length of pregnancy, and risk of preterm birth.

The analysis accounted for several factors that can be associated with birth outcomes, such as maternal age, body mass index, education, tobacco use during pregnancy, and timing of sample collection.

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 explore whether these chemicals are associated with other child health outcomes, such as neurodevelopment, obesity, and asthma.

 

Where can I learn more?

Access the full journal article, titled “Gestational exposure to ten classes of priority chemicals and birth outcomes in the ECHO Cohort” in JAMA Network Open.

 

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

 

Published June 17, 2026

Read the associated article.

Download this summary

Exposure to Multiple Chemicals During Pregnancy Associated with Adverse Birth Outcomes

Read More Related Research Summaries

Pre-, Peri-, and Postnatal

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 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

Read More Related Research Summaries

 

Prenatal Exposure to Phthalates, But Not Phthalate Replacements, Linked to Children’s Behavior, ECHO Study Finds

<< Back to Research Summaries

Prenatal Exposure to Phthalates, But Not Phthalate Replacements, Linked to Children’s Behavior, 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?

Phthalates are widely used chemicals that make plastics more flexible. During pregnancy, these chemicals can cross the placenta and may affect brain development. Although exposure to some phthalates has decreased over the past two decades, these chemicals and their replacements—such as DINCH and DEHTP—are still common, and little is known about their effects on children’s brain development. In this study, researchers examined many chemicals that form when the body breaks down phthalates and other plasticizers to see if exposure to these chemicals during pregnancy might be associated with behavioral problems in young children, including emotional reactivity, anxiety, depression, aggression, and attention problems.

 

What were the study results?

Researchers found that higher levels of two phthalate metabolites, mono-benzyl phthalate (MBzP) and mono-hexyl phthalate (MHxP), during pregnancy were associated with small to modest increases in externalizing behaviors (aggression and attention problems) in children aged 1.5–5 years. They did not find strong links between phthalate exposure and internalizing behaviors (emotional reactivity, anxiety, and depression), or between prenatal exposure to the phthalate replacement DINCH and any behavioral outcomes. 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.

 

What was the study's impact?

The study suggests that prenatal exposure to certain phthalates, but not to the alternative chemical DINCH, may be associated with increased externalizing behaviors in young children.

 

Who was involved?

Participants included 2,617 mother–child pairs from 13 ECHO Cohort study sites. Children’s behaviors were assessed at ages 1.5–5 years, and maternal urine samples were collected mostly during mid- to late-pregnancy.

 

What happened during the study?

During the study, prenatal maternal urine samples were analyzed for 27 chemical markers of phthalate exposure and six markers of exposure to non-phthalate replacements. Later, the children's behaviors were assessed using the Child Behavior Checklist for Ages 1½–5 (CBCL/1½–5). The researchers then used statistical methods to explore how levels of specific chemicals in the pregnant women’s body were linked to behaviors like emotional reactivity, anxiety, depression, aggression, and attention problems, and whether these links differed by child sex and neighborhood opportunity.

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 show how much pregnant women are exposed to di-n-hexyl phthalate (the parent compound of MHxP) and its effects on children’s brain development across different populations. Researchers may also study how different newer plasticizers affect brain development by looking at more recent participants and testing samples taken from mothers at several stages during pregnancy.

 

Where can I learn more?

Access the full journal article, 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,” 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

Prenatal Exposure to Phthalates, But Not Phthalate Replacements, Linked to Children’s Behavior, ECHO Study Finds

Read More Related Research Summaries