ECHO Study Finds Link Between Phthalate Exposure and Preterm Birth, Estimates Potential Costs

Authors: Leonardo Trasande, 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 found in some consumer products, and previous research has linked phthalate exposure to preterm birth. In response, the use of di-2-ethylhexyl phthalate (DEHP), a common type of phthalate, has decreased in recent years. However, there is limited research on the effects of the replacement phthalates, and the costs associated with phthalate exposure remain unquantified. ECHO Cohort researchers wanted to learn about the potential connections between phthalates, their metabolites in the urine of pregnant individuals, and birth outcomes—including birth weight and length of pregnancy. The study also sought to estimate the potential costs associated with adverse birth outcomes.

What were the study results?

When the researchers grouped mothers based on the amount of DEHP metabolites (substances produced when the body breaks down DEHP) found in their urine, they found that the 10 percent with the highest levels had a 50 percent higher chance of giving birth before the 37th week of pregnancy compared to the 10 percent with the lowest levels.

Some common alternatives to DEHP were associated with even higher risk of preterm birth. Women exposed to the highest amounts of these alternative chemicals—phthalic acid, di-isodecyl phthalate (DIDP), di-n-octyl phthalate (DnOP), and diisononyl phthalate (DiNP)—had twice the risk of preterm birth compared to those with little to no exposure to these alternatives.

Researchers estimated that the number of premature births in the U.S. that could be linked to phthalate exposure in 2018 was between 24,000 and 120,000, potentially costing between $1.6 billion and $8.1 billion in medical expenses over the lifetime of the children.

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 was this study's impact?

This ECHO Cohort research examines the effect of phthalates on birth outcomes such as preterm birth and birth weight. These findings associated adverse birth outcomes with exposure to DEHP and its chemically similar substitutes, which can inform the development of policies, programs, and practices that can help prevent or lessen potentially harmful exposures during pregnancy.

Who was involved?

The study included 5,006 mother-child pairs from 13 ECHO Cohort Study Sites across the U.S. Researchers included individuals with information on up to 20 urinary phthalate metabolites. The pregnant participants were aged 25 to 34 at the time they gave birth.

What happened during the study?

The researchers analyzed levels of 20 phthalate metabolites in urine samples collected at three points during each participant’s pregnancy. They also investigated the differences between specific types of phthalates, comparing DEHP with several newer alternatives developed to replace it. Then, the team looked for associations between these metabolite levels and preterm births. They also calculated the number of premature births that could be linked to phthalate exposure and the possible associated costs over the lifetime of the child.

What happens next?

Future research could look at how exposure to replacement phthalates affects child development after birth. The European Union has prohibited the use of certain phthalates in some consumer products—as have California and a few other U.S. states.

Where can I learn more?

Access the full journal article, titled “Prenatal phthalate exposure and adverse birth outcomes in the USA: a prospective analysis of births and estimates of attributable burden and costs,” in The Lancet Planetary Health.

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

Published February, 2024

Access the associated article.

Download this summary

ECHO Study Finds Link Between Phthalate Exposure and Preterm Birth, Estimates Potential Costs

Per- and Polyfluoroalkyl Substances (PFAS) Research and New Opportunities from the ECHO Program

Posted on July 18, 2023April 3, 2025 by Jodi Snare

This month’s Connector showcases a recent ECHO study that explores the relationship between maternal exposure to Per- and polyfluoroalkyl substances (PFAS) during pregnancy and obesity risk among children. You can learn more about all recent ECHO PFAS studies on ECHOChildren.org’s PFAS research webpage.

Additionally, ECHO is searching for its next Deputy Director to help shape the future of child health research as part of the leadership team for this unique program. I invite you to share this opportunity with your networks. You can learn more here.

We are also pleased to announce our two newest notices of funding opportunities. The awards from these opportunities for postdoctoral fellows and doctoral candidates, respectively, both provide a chance to study child health outcomes by performing secondary analyses of ECHO’s large longitudinal data sets within the Eunice Kennedy Shriver National Institute of Child Health and Development Data and Specimen Hub (DASH) repository. The knowledge and experience generated by these two opportunities will help ECHO pursue its goal of providing a national resource.

Social Media and Screen Time

ECHO Social Media and Screen Time Research

Questions

For more information, please email the NIH at NIHKidsandEnvironment@od.nih.gov.

Social media and digital tools have become part of daily life for many children and adolescents. While these platforms may offer a number of benefits, excessive screen time and digital media use among children have also been associated with adverse physical, developmental, and mental health outcomes, including obesity, inadequate sleep, and depression and anxiety. More research is needed to understand the full impact of screen time and social media use during developmentally sensitive periods of childhood and adolescence.

How can ECHO continue to advance research on the effects of digital media on child and adolescent health and well-being?

The ECHO Program is committed to understanding the factors that influence child health, well-being, and development. The ECHO Program’s uniquely diverse, nationwide research network collects information from more than 50,000 children and their families, including information about media habits and related health outcomes. This allows researchers to investigate the effects of digital media use on child health and well-being.

ECHO continues to publish new research on the role of digital media in child health and well-being. See below for a regularly updated list of ECHO publications investigating childhood screen use.

ECHO Screen Time Publications

How Has Children’s Screen Time Changed During the COVID-19 Pandemic?

Increases in screen time among children during the COVID-19 pandemic persisted more than one year into the pandemic, even when school closures and other restrictions had been lifted.

How Has the COVID-19 Pandemic Affected Children’s Health Behaviors?

Children’s screen time increased during the pandemic with Hispanic children and non-Hispanic Black children having the most noticeable increase in screen time.

How Have Changes in Family Situations Caused by the COVID-19 Pandemic Affected Children’s Behavior?

Children with parents who were able to change their work schedules to care for their children during the pandemic had less screen time and slept longer at night compared to children with parents who were unable to adjust their work schedules due to stress about money and access to food.

How Can Clinicians Help Parents Set Reasonable Boundaries for their Children’s Digital Media Use?

Parents have varying knowledge and beliefs when it comes to regulating their children’s digital media use, but many parents are interested in learning more about this topic from materials provided by their child’s pediatrician.

NIH Study Links Prenatal Per- and Polyfluoroalkyl Substance Exposure to Higher BMI & Obesity Risk in Children

Posted on June 7, 2023August 27, 2025 by Jodi Snare

FOR IMMEDIATE RELEASE

Exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy was linked to slightly higher BMIs and an increased risk of obesity in children, according to new research funded by the Environmental influences on Child Health Outcomes Program (ECHO) at the National Institutes of Health.

“There is a growing interest in understanding the effects of PFAS exposure on children’s health,” said Joseph Braun, PhD, of Brown University. “Studies like this one can help researchers and policymakers better understand the risks of PFAS to take effective actions to protect vulnerable populations.”

The researchers analyzed the levels of seven different PFAS in blood samples collected from mothers during pregnancy. These so-called “forever chemicals” are long-lasting substances that can be found in many household materials, as well as food and drinking water.

Researchers then calculated each child’s BMI, an approximate measure of body fat. Higher levels of PFAS in mother’s blood were related to slightly higher BMIs and increased risk of obesity were seen equally for male and female children.

The study used data collected over two decades from 1,391 children between the ages of 2 and 5 years and their mothers who were enrolled in eight ECHO research sites in California, Illinois, Massachusetts, Colorado, New Hampshire, Georgia, and New York.

Future studies will examine the associations between maternal PFAS exposure and obesity-related health outcomes in older children.

Dr. Braun and Yun Liu, PhD, ECHO Program investigators at Brown University, led this collaborative research published in Environmental Health Perspectives.

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About ECHO: ECHO is a nationwide research program supported by the NIH. Launched in 2016, ECHO aims to enhance the health of children for generations to come. ECHO investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

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

Media Contacts

For information or to request an interview, contact Rebekah Yeager, rebekah.yeager@nih.gov.

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

Connect With Us

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 @ECHOChildHealth for the latest ECHO Program updates on Twitter.

Maternal PFAS Exposure During Pregnancy Increases Children’s Risk of Obesity

<< Back to Research Summaries

Maternal PFAS Exposure During Pregnancy May Increase Children’s Risk of Obesity

Authors: Yun Liu, Joseph Braun, et al.

Who sponsored this study?

This research was supported by the Environmental influences on Child Health Outcomes (ECHO) Program, Office of The Director, National Institutes of Health.

Why was this study needed?

Per- and polyfluoroalkyl substances (PFAS) are long-lasting chemicals that can be found in many household materials, as well as food and drinking water. Maternal PFAS exposure during pregnancy may be linked to increased weight and a higher risk of obesity among children and adolescents. However, existing studies looking at these associations have had inconsistent findings.

What were the study results?

The study found that higher levels of some PFAS were linked with slightly higher BMIs in children and an increased risk of obesity. This trend was seen across male and female children and wasn’t affected by the presence of other factors linked to childhood obesity.

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 was this study's impact?

Recently, there has been growing interest in understanding the effects of PFAS exposure on children’s health and establishing policies to address PFAS pollution. The US Environmental Protection Agency (EPA) has created a Roadmap to address PFAS contamination. Studies like this one can help better understand the risks of PFAS to take effective actions to protect vulnerable populations.

Who was involved?

The researchers used data from 1,391 children between the ages of 2 and 5 years and their mothers who were enrolled in eight ECHO cohorts across United States from 1999 to 2019.

What happened during the study?

The researchers measured levels of seven different PFAS in maternal blood samples collected during pregnancy. The researchers also used data on children’s weight and height to calculate each child’s body mass index (BMI), an approximate measure of body fat.

What happens next?

Future studies are needed to examine potential links between maternal PFAS exposure during pregnancy and obesity-related health concerns in older children.

Where can I learn more?

Access the full journal article, titled “Associations of Gestational Perfluoroalkyl Substances Exposure with Early Childhood BMI Z-Scores and Risk of Overweight/Obesity: Results from the ECHO Cohorts,” in Environmental Health Perspectives.

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

Published June 7, 2023

Access the associated article.

See ECHO's PFAS research.

Download this summary

Maternal PFAS Exposure During Pregnancy May Increase Children’s Risk of Obesity

ECHO Researchers Reveal Link Between PFAS Exposure During Pregnancy and Childhood Obesity Risk

Posted on June 7, 2023July 24, 2023 by Jodi Snare

Collaborative ECHO research led by Yun Liu, PhD and Joseph Braun, PhD of Brown University investigates the relationship between maternal exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy and obesity risk among children and adolescents. The research team evaluated maternal PFAS levels during pregnancy and child body mass index (BMI) for 1,391 mother-child pairs across eight ECHO cohorts. The researchers found that higher levels of some PFAS during pregnancy were associated with higher BMIs and an increased risk of obesity in children. This research, titled “Associations of Gestational Perfluoroalkyl Substances Exposure with Early Childhood BMI Z-Scores and Risk of Overweight/Obesity: Results from the ECHO Cohorts,” is published in Environmental Health Perspectives.

This study included women who were pregnant between 1999-2019 in California, Illinois, Massachusetts, Colorado, New Hampshire, Georgia, and New York and their children who were evaluated between the ages of 2 and 5 years old. The researchers analyzed the levels of seven different PFAS in blood samples collected from mothers during pregnancy. They then used the children’s height and weight data to calculate their BMI, an approximate measure of body fat, while accounting for each child’s age and sex, as well as other factors related to PFAS exposure and body fat.

“There is growing interest in understanding the effects of PFAS exposure on children’s health,” said Dr. Braun. “Studies like this one will help researchers and policymakers better understand the risks of PFAS in order to take effective actions to protect vulnerable populations.”

Going forward, future studies will examine the associations between maternal PFAS exposure and obesity-related health outcomes in older children.

Read the research summary.

ECHO’s PFAS Research

ECHO PFAS Research

Questions

For more information, please email the NIH at NIHKidsandEnvironment@od.nih.gov.

Per- and polyfluoroalkyl substances (PFAS) are a group of manufactured chemicals that are used in a wide variety of industry and consumer products. These substances are known as “forever chemicals” because they break down very slowly, persist in the environment, and accumulate in people and animals. PFAS can be found in many household materials, personal care products, food, and drinking water. Many people can be exposed to PFAS through their environment, occupation, or use of contaminated water, products, or packaging.

Current research suggests that high levels of some PFAS may be associated with adverse health outcomes, including pregnancy outcomes, neurological impairments, and obesity. The full scope of health effects on families in the United States is not fully understood, given the number of PFAS chemicals used in products and the potential ways PFAS exposures can occur.

How can ECHO continue to advance PFAS research?

The ECHO Program is committed to understanding how environmental exposures, including exposures to PFAS and other widespread chemical substances, influence the health and well-being of children and their families. The ECHO Program’s uniquely diverse, nationwide research network includes more than 50,000 children and allows researchers to investigate the effects of chemical exposures on child health outcomes.

ECHO continues to publish new research on the effects of PFAS exposure. See below for an ongoing list of ECHO publications investigating PFAS.

ECHO PFAS Publications

How Does Maternal PFAS Exposure During Pregnancy Affect Children’s Risk of Obesity?

Higher levels of some PFAS during pregnancy were linked with slightly higher body mass index (BMI) in children and increased risk of obesity.

What are the Effects of Prenatal PFAS Exposure on Birthweight?

PFAS were found in almost all study participants, and participants with higher levels of PFAS in their blood were more likely to have babies born at lower birthweights compared to those with lower levels of PFAS exposure.

Does Prenatal PFAS Exposure Affect a Child’s Risk for Developing Autism-related Traits?

Prenatal exposure to one specific PFAS, perfluorononanoic acid (PFNA), may be associated with an increase in autism-related traits in children.

What is the Effect of Maternal PFAS Exposure on Prenatal Growth in Black Women?

Some PFAS exposures were associated with greater risk of low birthweight or changes in the levels of key molecules related to infant development.

NIH Study Links Low Birthweight to Prenatal Per- and Polyfluoroalkyl Substances (PFAS) Exposure

Posted on March 15, 2023August 27, 2025 by Jodi Snare

FOR IMMEDIATE RELEASE

High exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy may be associated with lower birthweights, according to a new study funded by Environmental influences on Child Health Outcomes Program (ECHO) at the National Institutes of Health.

PFAS are widely used, long lasting chemicals, also known as “forever chemicals,” that break down slowly over time and can be found in drinking water, food, household products, personal care products, manufacturing facilities, and other sources.

“Outside of research studies, pregnant women are not tested for PFAS and are uncertain of the potential harms PFAS can cause,” said Amy Padula, PhD, MSc, an ECHO Program investigator at the University of California, San Francisco. “We need to better understand where people are most likely to be exposed to these substances given the number of sources, from drinking water to consumer products.”

This is the largest study to date to examine the role of PFAS in birth outcomes, involving more than 3,000 pregnant participants from 11 different ECHO research sites across the United States. Researchers measured PFAS levels in pregnant participants’ blood samples and found that the risk of giving birth to a baby of low birthweight increases with higher levels of these chemicals.

Dr. Padula and Tracey Woodruff, PhD, MPH, ECHO Program investigators at the University of California, San Francisco led this collaborative research published in Environmental Health Perspectives.

Padula, A. et al. Birth Outcomes in Relation to Prenatal Exposure to Per- and Polyfluoroalkyl Substances and Stress in the Environmental influences on Child Health Outcomes (ECHO) Program. Environmental Health Perspectives. DOI: 10.1289/EHP10723

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About ECHO: ECHO is a nationwide research program supported by the NIH. Launched in 2016, ECHO aims to enhance the health of children for generations to come. ECHO investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

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

Media Contacts

For information or to request an interview, contact Rebekah Yeager, rebekah.yeager@nih.gov.

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

Connect With Us

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 @ECHOChildHealth for the latest ECHO Program updates on Twitter.

ECHO Study Suggests Exposure to PFAS During Pregnancy May Be Linked to Lower Birthweights

<< Back to Research Summaries

ECHO Study Suggests Exposure to PFAS During Pregnancy May Be Linked to Lower Birthweights

Authors: Amy Padula, Tracey Woodruff, et al.

Who sponsored this study?

This research was supported by the Environmental influences on Child Health Outcomes (ECHO) program, the Office of the Director, and the National Institutes of Health.

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

What were the study results?

PFAS were found in almost all participants in the study. Researchers also found that in this study, participants with higher levels of PFAS exposure were more likely to have babies born with lower birthweight. These results did not find that stress played a role in the relationship between PFAS exposure and birthweight.

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 was this study's impact?

The results of this study suggest that PFAS exposure during pregnancy is associated with lower birthweight in infants. However, outside of research studies, pregnant women are not usually tested for PFAS and are often unaware of their potential harms despite PFAS exposure from the environment being common. Therefore, it is important to address efforts to reduce and prevent further exposure to PFAS. Researchers need to better understand where people are most likely to be exposed to these chemicals given the wide range of exposure sources, from PFAS contamination in water to PFAS used in certain consumer products.

Why was this study needed?

It is important to know what the effects of per- and polyfluoroalkyl substances (PFAS) exposures may be on child and maternal health. This study is the largest of its kind and includes participants from across the US to help inform future research related to potential effects of PFAS exposures.

Who was involved?

This study included eleven ECHO pregnancy cohorts with a total of 3,339 participants from several states.

What happened during the study?

The researchers measured the concentration of PFAS, chemicals used in a wide range of consumer products, in the blood of pregnant women. They also surveyed these women about their stress levels throughout pregnancy. These measurements occurred over the past 20 years. The researchers then compared the birthweight for babies resulting from these pregnancies and recorded any instances of preterm birth.

What happens next?

The next step for researchers is to examine potential sources of PFAS exposures, including exposures from drinking water and consumer products. Future studies within ECHO may also examine how body mass index and preexisting conditions, such as diabetes during pregnancy or high blood pressure, may interact with PFAS exposures and contribute to the effects of PFAS on infant birthweight. Future studies may also examine additional chemicals that could contribute to lower birthweight in infants.

Where can I learn more?

The US Environmental Protection Agency (EPA) created a Roadmap to protect people and communities from PFAS contamination.

Access the full journal article, titled “Birth Outcomes in Relation to Prenatal Exposure to Per- and Polyfluoroalkyl Substances and Stress in the Environmental influences on Child Health Outcomes (ECHO) Program” in Environmental Health Perspectives.

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

Published March 15, 2023

Access the associated article.

Download this summary

ECHO Study Suggests Exposure to PFAS During Pregnancy May Be Linked to Lower Birthweights

ECHO Researchers Investigate the Effect of Prenatal PFAS Exposure on Birthweight

Posted on March 15, 2023April 2, 2025 by Jodi Snare

In a study investigating how per- and polyfluoroalkyl substances (PFAS) exposures affected pregnant mothers and their babies, ECHO researchers Amy Padula, PhD, MSc, and Tracey Woodruff, PhD, MPH, from the University of California, San Francisco found that higher levels of prenatal exposure to PFAS are associated with lower birthweights. The PFAS were detected in all participating mothers, suggesting some level of PFAS exposure from the environment. PFAS are widely used, long lasting chemicals that break down very slowly over time and are found in drinking water, food, household products, personal care products, manufacturing facilities, and other sources.

This research, titled “Birth Outcomes in Relation to Prenatal Exposure to Per- and Polyfluoroalkyl Substances and Stress in the Environmental influences on Child Health Outcomes (ECHO) Program,” is published in Environmental Health Perspectives.

For this study, the researchers collected blood samples and pregnancy data from more than 3,000 pregnant women in 11 different ECHO cohorts. They then measured PFAS levels in the mothers’ blood samples and asked them about their stress levels during pregnancy. The team found that mothers who had higher levels of PFAS chemicals in their bodies were more likely to give birth to a baby of low birth weight than mothers with lower levels of PFAS. Additionally, previous studies have found that psychosocial stress may affect PFAS exposures and birthweight. However, the team did not find that stress played a role in the relationships between low birthweight and PFAS exposure.

This research suggests that PFAS exposures during pregnancy can affect infant birth weight, demonstrating the importance of efforts to reduce sources of environmental PFAS exposure. “Outside of research studies, pregnant women are not tested for PFAS and are uncertain of the potential harms PFAS cause,” said Dr. Padula. “We need to better understand where people are most likely to be exposed to these substances given the number of sources, from drinking water to consumer products.”

The next steps for this research include examining potential sources of PFAS exposure. Additional studies may examine how factors like body mass index and other health conditions in pregnancy might additionally affect the relationship between PFAS exposure and infant birthweight.

The US Environmental Protection Agency (EPA) has created a Roadmap to address PFAS as part of the Biden Administration plan to accelerate efforts to better protect Americans from PFAS exposure.

Read the research summary.