Exposure to Certain PFAS Associated with Maternal Depression & Stress for Pregnant and Postpartum Mothers, ECHO Study Finds

Posted on January 12, 2026January 12, 2026 by Jodi Snare

Exposure to certain per- and polyfluoroalkyl substances (PFAS) was associated with changes in depression and stress for pregnant and postpartum mothers, according to a new ECHO Cohort study led by Susanna Mitro, PhD and Lyndsay Avalos, PhD, MPH of Kaiser Permanente Northern California.

PFAS are a large, complex group of synthetic chemicals found in some household products such as cookware and stain-resistant fabrics. These substances are often referred to as “forever chemicals” because they don’t break down easily, causing them to build up over time in water, soil, and air. Previous studies have shown that PFAS can negatively affect the brain, and there is conflicting evidence about their potential effects on depression and perceived stress during and after pregnancy. This study included 4,403 pregnant participants from 16 ECHO Cohort study sites across the United States. Researchers measured the levels of seven PFAS in the mother’s blood during pregnancy, and participants reported on their depression and stress symptoms before and after giving birth.

Key Takeaways include:

Higher levels of N-methyl perfluorooctane sulfonamido acetic acid (N-MeFOSAA) were associated with slightly higher depressive symptoms and perceived stress, especially postpartum, while higher perfluorodecanoic acid (PFDA) levels were associated with a lower risk of diagnosed depression and lower prenatal perceived stress.
Exposure to perfluorooctanesolfonic acid (PFOS) showed a mixed pattern where moderate exposure was associated with increased depression risk, but the highest exposure was associated with lower depression risk.
When looking at all seven PFAS types as a group, there was generally no strong link to depression diagnosis or severity, but the data did show higher stress at low to moderate exposures, but lower stress as high exposure.
The effects of PFAS were different depending on social factors. For example, people who were not born in the U.S. or who had higher social vulnerability sometimes showed stronger links between PFAS and depression or stress.

“This study adds to mounting evidence that PFAS exposure during pregnancy may have negative health impacts on the pregnant individual, reinforcing the importance of minimizing exposure to PFAS during this sensitive time,” said Dr. Mitro.

Overall, the associations observed in this study were small, so more research is needed to fully understand the effects of PFAS on pregnancy mental health. Future studies could also help researchers clarify the biological mechanisms linking PFAS exposure to depression and stress and explore the role of social factors in influencing these associations.

This collaborative research, titled “Gestational PFAS concentrations in association with maternal depression and perceived stress during pregnancy and postpartum in the ECHO cohort,” is published in Environmental Research.

ECHO Study Finds Association Between Exposure to Certain PFAS and Maternal Depression & Stress During/After Pregnancy

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ECHO Study Finds Association Between Exposure to Certain PFAS and Maternal Depression & Stress During/After Pregnancy

Authors: Susanna D. Mitro, Lyndsay Avalos, 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?

Per- and polyfluoroalkyl substances (PFAS) are a large, complex group of synthetic chemicals found in some household products such as cookware and stain-resistant fabrics. These substances are often referred to as “forever chemicals” because they don’t break down easily, causing them to build up over time in water, soil, and air. Previous studies have shown that PFAS can negatively affect the brain, and there is conflicting evidence about their potential effects on depression and perceived stress during and after pregnancy. Depression and stress during these periods are common and linked to adverse health outcomes for both parents and children. This study aimed to clarify whether PFAS exposure during pregnancy is associated with an increased risk of depression and stress, and whether social factors affect these associations.

What were the study results?

Of the seven PFAS included in this study, some types were linked to changes in depression and stress for pregnant and postpartum participants. For example, higher levels of N-methyl perfluorooctane sulfonamido acetic acid (N-MeFOSAA) were associated with slightly higher depressive symptoms and perceived stress, especially postpartum, while higher perfluorodecanoic acid (PFDA) levels were associated with a lower risk of diagnosed depression and lower prenatal perceived stress. Exposure to perfluorooctanesolfonic acid (PFOS) showed a mixed pattern where moderate exposure was associated with increased depression risk, but the highest exposure was associated with lower depression risk.

When looking at all seven PFAS types as a group, there was generally no strong link to depression diagnosis or severity, but the data did show higher stress at low to moderate exposures, but lower stress as high exposure. The effects of PFAS were different depending on social factors. For example, people who were not born in the U.S. or who had higher social vulnerability sometimes showed stronger links between PFAS and depression or stress.

What was this study's impact?

Overall, the associations observed in this study were small, so more research is needed to fully understand the effects of PFAS on pregnancy mental health. This study adds to mounting evidence that PFAS exposure during pregnancy may have negative health effects during pregnancy, reinforcing the importance of minimizing exposure to PFAS during this sensitive time.

Who was involved?

The study included 4,403 pregnant participants from 16 ECHO Cohort study sites.

What happened during the study?

Researchers measured the levels of seven PFAS in the mother’s blood during pregnancy. Pregnant participants reported whether they received a diagnosis of depression during pregnancy and filled out surveys on their depression and stress symptoms before and after giving birth. The researchers then used statistical methods to evaluate potential associations between PFAS exposure and mental health outcomes and how social factors may have influenced these associations.

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 clarify the biological mechanisms linking PFAS exposure to depression and stress and explore the role of social factors in influencing these associations.

Where can I learn more?

Access the full journal article, titled “Gestational PFAS concentrations in association with maternal depression and perceived stress during pregnancy and postpartum in the ECHO cohort,” in Environmental Research.

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

Published December 1, 2025

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ECHO Study Finds Association Between Exposure to Certain PFAS and Maternal Depression & Stress During/After Pregnancy

PFAS Exposures During Pregnancy Not Significantly Associated with Child Behavior Issues

Posted on September 22, 2025September 22, 2025 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.

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PFAS Exposure During Pregnancy Not Associated with Behavior Issues in Children, ECHO Study Finds

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PFAS Exposure During Pregnancy Not Associated with Behavior Issues in Children, ECHO Study Finds

Author(s): Catherine Bulka, Rebecca Fry, 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?

Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of man-made chemicals used in some consumer and industrial products like cookware, stain-resistant fabrics, and foams used to fight fires. These substances 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 looked at the relationship between PFAS exposure during pregnancy and child behavior using harmonized measurements collected from many mother-child pairs from across the United States.

What were the study results?

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. However, 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.

What was the study's impact?

While most PFAS showed no association with behavioral problems, some suggestive, non-linear relationships emerged, indicating that these exposures may influence brain development in complex and unexpected ways. Overall, the study did not find strong or steady links between PFAS exposure during pregnancy and child behavior problems. More research may be needed, especially about newer PFAS replacement chemicals and exposures that happen after birth.

Who was involved?

The study included children from nine ECHO Cohort study sites across the U.S., including 1,723 preschool-age children (1.9-5.9 years) and 627 school-age children (6-15 years).

What happened during the study?

During the study, researchers measured PFAS levels in blood samples collected from mothers between 2- and 42-weeks’ gestation. Later, the researchers assessed children’s behavior using the Child Behavior Checklist (CBCL) when they were preschool- or school-aged. They then used statistical methods to evaluate potential associations between prenatal exposure to PFAS and PFAS mixtures and child behavioral problems.

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 assess the effects of PFAS exposures during the postnatal period, which may be a more relevant window for childhood brain development and behavioral issues. Additionally, 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.

Where can I learn more?

Access the full journal article, titled “Prenatal Exposure to Per- and Polyfluoroalkyl Substances: Association with Child Behavior 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 September 5, 2025

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PFAS Exposure During Pregnancy Not Associated with Behavior Issues in Children, ECHO Study Finds

NIH Study Finds Association Between PFAS Exposures During Pregnancy and Changes in Maternal Gut Microbiome

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

Exposure to per- and polyfluoroalkyl substances (PFAS)—man-made chemicals found in a variety of consumer products and contaminated water, air, and food—during pregnancy was associated with changes in maternal gut microbiome, according to a new study funded by the National Institutes of Health (NIH) Environmental influences on Child Health Outcomes (ECHO) Program.

The composition of the gut microbiome is dependent on factors including diet, lifestyle, and exposure to environmental chemicals, and has implications for human health. “Changes in the maternal microbiome may impact multiple pregnancy health outcomes related to metabolism and inflammation, thus it is important to identify environmental factors such as PFAS that can modulate microbiome form and function,” said ECHO Cohort investigator Michael Petriello, PhD of Wayne State University.

Key takeaways include:

Prenatal PFAS exposure was significantly associated with the relative abundance of specific types of bacteria in the maternal gut microbiome.
Associations between PFAS exposure and the gut microbiome differed by study location, with some bacteria present in one location but not the other.
In both sites, prenatal PFAS exposure did not have a significant effect on the diversity of microbes in the maternal gut microbiome.

The effect of PFAS exposure on maternal gut microbiome composition may have broader implications for the health of both the mother and baby.

“It is important to decrease exposure to pollutants such as PFAS, but complementary interventions focused on improving microbiome health and resiliency may also help to decrease the toxicity of environmental chemicals,” said Dr. Petriello.

This collaborative research, titled “Prenatal PFAS exposure and outcomes related to microbiome composition and diversity in later pregnancy,” is published in Environmental Research.

PFAS Exposure Associated with Changes in Gut Microbiome During Pregnancy

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PFAS Exposure Associated with Changes in Gut Microbiome During Pregnancy

Authors: Michael Petriello, 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?

Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of man-made chemicals that are used in various industrial processes and consumer products, including cookware, stain-resistant fabrics, and foams used to fight fires. PFAS can also build up in the environment, contaminating water, food, and air. Because PFAS can last a long time without breaking down, these chemicals can also build up in biological tissues, including the gut lining. PFAS exposure has previously been linked to diseases of the cardiovascular, immune, endocrine, reproductive, and metabolic systems.

Recent studies have shown that PFAS exposure may affect a person’s gut microbiome, the ecosystem of bacteria and other microbes that live in the gut. The composition of the gut microbiome is dependent on a variety of factors, including diet, lifestyle, and exposure to environmental chemicals. These microbes often help aid digestion, support immune health, or protect against pathogens. Changes in the maternal microbiome may impact multiple pregnancy health outcomes related to metabolism and inflammation. Therefore, it is important to identify environmental factors that may affect microbiome health during pregnancy.

What were the study results?

In both sites, prenatal PFAS exposure did not have a significant effect on the diversity of microbes in the maternal gut microbiome. However, the study found there was a significant association between prenatal PFAS exposure and the relative abundance of specific types of bacteria in the maternal gut microbiome. Associations between PFAS exposure and gut microbiome varied by study site, with certain types of bacteria being site-specific and not shared between the Michigan and Atlanta sites.

What was this study's impact?

The effect of PFAS exposure on maternal gut microbiome composition may have broader implications for the health of both the mother and baby. Decreasing exposure to pollutants such as PFAS can improve health outcomes, but complimentary interventions focused on improving microbiome health and resiliency may also help to combat the health effects of environmental chemicals.

Who was involved?

The study included 162 pregnant participants from ECHO study sites in Atlanta and Michigan. The Michigan site (Michigan Archive for Research on Child Health Cohort) included 61 predominantly non-Hispanic White (90.2%) participants. The Atlanta site (Atlanta African American Maternal Child Cohort) included 101 participants who self-identified as Black or African American (100%).

What happened during the study?

Researchers measured PFAS exposure during early or late pregnancy. Later in pregnancy, researchers collected microbiome samples from the mother’s stool to evaluate the types of bacteria present and the bacterial diversity. Statistical methods were used to understand the relationship between PFAS exposure and microbiome composition and diversity.

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 understand how these microbiome changes are related to maternal and child health outcomes.

Where can I learn more?

Access the full journal article, titled “Prenatal PFAS exposure and outcomes related to microbiome composition and diversity in later pregnancy,” in Environmental Research.

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

Published August 15, 2025

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PFAS Exposure Associated with Changes in Gut Microbiome During Pregnancy

New ECHO Research Investigates Association Between PFAS Exposure and Bioactive Lipids in Pregnant Participants

Posted on August 20, 2024 by Jodi Snare

Collaborative ECHO research led by Himal Suthar, MIDS and Max Aung, PhD of the University of Southern California, Los Angeles investigates the association between the concentration of per- and polyfluoroalkyl substances (PFAS) in the blood of pregnant participants with levels of bioactive lipids from three metabolic pathways. This research, titled “Cross-Sectional Associations between Prenatal Per- and Poly-Fluoroalkyl Substances and Bioactive Lipids in Three Environmental Influences on Child Health Outcomes (ECHO) Cohorts,” is published in Environmental Science and Technology.

PFAS are a large, complex group of synthetic chemicals that have been used in consumer products around the world since about the 1950s. They are found in items such as non-stick cookware, stain-resistant fabrics, and firefighting foam. People are most likely exposed to these chemicals through contaminated water or food, using products containing PFAS, or breathing air with PFAS particles.

Because PFAS break down slowly, if at all, people and animals are repeatedly exposed to them, and blood levels of some PFAS can build up over time. Scientific studies have identified multiple health effects associated with PFAS exposure. Women exposed to PFAS during pregnancy are at increased risk for adverse birth outcomes and pregnancy complications.

Changes in bioactive lipids—metabolic and inflammation pathway indicators—have been linked to PFAS exposure and adverse pregnancy outcomes. Widespread evidence of human PFAS exposure and PFAS’ association with pregnancy outcomes warranted a detailed investigation into intermediate mechanisms of PFAS toxicity to inform risk assessment and develop potential interventions.

In this study, the research team estimated associations between 50 plasma bioactive lipids and 12 serum PFAS, in pairs and as a mixture, in 414 pregnant participants from three ECHO study sites. Serum PFAS was measured using liquid chromatography and tandem mass spectrometry. Plasma bioactive lipids were measured using mass spectrometry. Associations between prenatal PFAS exposure and bioactive lipids were quantified using various statistical analyses while controlling for several factors (e.g., maternal age, gestational age at sample collection, maternal education, pre-pregnancy BMI).

When researchers looked at data from different study sites, they found that higher levels of PFAS in blood were often linked with higher levels of certain bioactive lipids. The research team also noticed differences in the distribution of bioactive lipids between individual study sites, possibly driven by variations in the genetic makeup and sociodemographic characteristics of the populations or differences in environmental exposures due to diet.

Researchers found that the similar results from analyzing mixtures of and individual PFAS chemicals indicate that specific bioactive lipids could serve as useful biomarkers of PFAS exposure.

“Findings from our present study contextualize potential clinical care approaches proposed by the National Academies of Science, Engineering, and Medicine by providing details on specific prenatal lipid metabolite and PFAS exposure associations,” Suthar said. “While the bioactive lipids measured in this study have not yet been tested as routine biomarkers in clinical settings, these findings aid in advancing the future of healthcare as additional and more complex lipid biomarkers become measurable and are tested for clinical use.”

The researchers plan to measure associations between bioactive lipids and perinatal mental health outcomes including perinatal and postpartum depression. Future studies could also look at the influence of other variables on this relationship. For example, researchers could investigate the influence of diet, which has been linked to changes in both PFAS and bioactive lipid concentrations.

Read the research summary.

ECHO Cohort Study Finds Association Between PFAS and Bioactive Lipids

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ECHO Cohort Study Finds Association Between PFAS and Bioactive Lipids

Authors: Himal Suthar, Max Aung, 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?

Per- and polyfluoroalkyl substances (PFAS) are a large, complex group of synthetic chemicals that have been used in consumer products around the world since about the 1950s. They are ingredients in various everyday products. For example, PFAS are used to keep food from sticking to packaging or cookware, make clothes and carpets resistant to stains, and create firefighting foam that is more effective. People are most likely exposed to these chemicals by consuming PFAS-contaminated water or food, using products made with PFAS, or breathing air containing PFAS.

Because PFAS break down slowly, if at all, people and animals are repeatedly exposed to them, and blood levels of some PFAS can build up over time. Scientific studies have identified multiple health effects associated with PFAS exposure.[1] Women exposed to PFAS during pregnancy are at increased risk for adverse birth outcomes and pregnancy complications.

Lipids are fatty molecules that perform a variety of functions in the body—from forming the membranes of cells to serving as a building block for certain hormones. Changes in bioactive lipids—broadly defined as a category of lipids with signaling properties that cause biological effects and changes in the body—have been linked to PFAS exposure and adverse pregnancy outcomes. This study aimed to compare the concentration of PFAS in the blood of pregnant participants with levels of bioactive lipids in three important metabolic pathways.

[1] National Institute of Environmental Health Sciences: Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) (nih.gov)

What were the study results?

The research team analyzed the associations between 12 types of PFAS, in pairs and as mixtures, and 50 bioactive lipids in blood plasma in pregnant participants across three ECHO Cohort Study Sites. When researchers looked at data from different study sites, they found that higher levels of PFAS in blood were often linked with higher levels of certain bioactive lipids. The research team also noticed differences in the distribution of bioactive lipid compounds between individual study sites, possibly driven by variations in the genetic makeup and sociodemographic characteristics of the populations or differences in environmental exposures due to diet.

Footnote: Results reported here are for a single study and reflect an observed correlation. Other or future studies may provide new information or different results. You should always consult with a qualified healthcare provider for diagnosis and for answers to your personal questions.

What was this study's impact?

The similarity of results researchers found from the analysis of mixtures of PFAS chemicals and individual PFAS chemicals indicate that specific bioactive lipids could be useful biomarkers of PFAS exposure. Biomarkers are biological indicators of a particular health effect or status – in this case, PFAS exposure. They can be found in blood, urine, or other body fluids and can be substances, characteristics, genes, or proteins. This insight could help in understanding and addressing the health effects of PFAS by expanding screening methods.

The bioactive lipids measured in this study have not yet been tested as routine biomarkers in clinical settings. However, these findings aid in advancing the future of healthcare as additional and more complex lipid biomarkers become measurable and are tested for clinical use.

These findings encourage researchers to prioritize the study of PFAS and bioactive lipids pairs in future testing in addition to individually studying the effect of different types of PFAS. Additionally, this study highlights the importance of regulating the 12 types of PFAS observed.

Who was involved?

This study included 414 pregnant participants from three ECHO Cohort study sites: Chemicals in Our Bodies based in San Francisco, ECHO-PROTECT based in Puerto Rico, and Illinois Kids Development Study based in Chicago.

What happened during the study?

The research team estimated associations between prenatal PFAS exposure and bioactive lipids, measuring the levels of 12 types of PFAS and 50 bioactive lipids in 414 pregnant participants. Researchers quantified associations by using various statistical analyses while controlling for several factors (e.g., maternal age, gestational age at sample collection, maternal education, pre-pregnancy BMI).

What happens next?

The researchers plan to measure associations between bioactive lipids and peri- and prenatal mental health outcomes including perinatal and postpartum depression. Future studies could also look at the influence of other variables on this relationship. For example, researchers could investigate the influence of diet, which has been linked to changes in both PFAS and bioactive lipid concentrations.

Where can I learn more?

Access the full journal article, titled “Cross-Sectional Associations between Prenatal Per- and Poly-Fluoroalkyl Substances and Bioactive Lipids in Three Environmental Influences on Child Health Outcomes (ECHO) Cohorts,” in Environmental Science and Technology.

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

Published May 14, 2024

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ECHO Cohort Study Finds Association Between PFAS and Bioactive Lipids

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

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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

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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.

ECHO Study Finds Association Between Exposure to Certain PFAS and Maternal Depression & Stress During/After Pregnancy

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PFAS Exposure During Pregnancy Not Associated with Behavior Issues in Children, ECHO Study Finds

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PFAS Exposure Associated with Changes in Gut Microbiome During Pregnancy

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ECHO Cohort Study Finds Association Between PFAS and Bioactive Lipids

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

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