chemicals

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

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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

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Exposure to Multiple Chemicals During Pregnancy Associated with Adverse Birth Outcomes

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Pre-, Peri-, and Postnatal

Young Children Show Widespread Exposure to Environmental Chemicals, ECHO Study Finds

Posted on by Jodi Snare

Children had higher levels of certain replacement chemicals compared to their mothers during pregnancy.

Young children are exposed to a wide range of environmental chemicals, including some emerging and replacement chemicals, according to ECHO Cohort research measuring early childhood exposures. This study found that children aged 2 to 4 years often had higher levels of certain chemicals compared to their mothers during pregnancy, highlighting potential risks for future health.

Researchers measured 111 different chemicals in urine samples from 201 children and their mothers from six ECHO Cohort study sites across the United States. More than half of the children’s samples contained multiple chemicals, such as environmental phenols, pesticides, phthalates, and markers of exposure to polycyclic aromatic hydrocarbons (PAHs). Approximately 34 chemicals were found in over 90% of the samples, including nine of which have not been included in U.S. national biomonitoring.

Compared to their mothers, children showed higher levels of chemicals like bisphenol S (BPS), used in hard plastics and synthetic fibers, and compounds related to pesticides. By contrast, mothers had higher levels of chemicals such as triclosan and monoethyl phthalate (MEP), which are found in some soaps and cosmetics.

“Finding so many chemicals detected in over 90% of young children reinforces the concern that our children are being exposed to a sea of potentially harmful compounds from their earliest years, with little parents can do to protect them”, said Deborah Bennett, PhD of the University of California, Davis.

Over time, exposures to chemicals like triclosan, parabens, phthalates, and PAHs have become less common, likely due to regulations and bans. However, replacement chemicals such as DINCH—a phthalate substitute in some plastics—and certain pesticides have been increasingly detected.

This collaborative research, titled “Early Childhood Exposures to Environmental Chemicals in the Environmental influences on Child Health Outcomes Consortium,” is published in Environmental Science & Technology.

Young Children May Be Exposed to a Variety of Emerging Chemicals Found in Some Consumer Products

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Young Children May Be Exposed to a Variety of Emerging Chemicals Found in Some Consumer Products

Author(s): Jiwon Oh, Deborah H. Bennett, 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?

Over time, exposure to chemicals like triclosan, parabens, phthalates, and PAHs became less common, likely because of new rules and bans on their use. However, replacement chemicals—like DINCH, a chemical that has replaced phthalates in some plastic products—and some pesticides have been showing up more often in later years. Exposure to multiple chemicals during pregnancy and early childhood is a concern because these are critical stages of development when children are more vulnerable to harm. Such exposures can increase their risk of health problems later in life. There is limited data tracking young children’s – 2 to 4 years - exposure to environmental chemicals compared to older children. Prenatal and early-life exposure to these chemicals can increase the risk of multiple adverse child health outcomes. This study aimed to investigate early childhood exposures to a variety of environmental chemicals.

 

What were the study results?

Scientists measured 111 different chemicals in urine samples from young children and their mothers during pregnancy. More than half of the samples contained chemicals such as environmental phenols, pesticides, phthalates, and chemical markers of exposure to polycyclic aromatic hydrocarbons (PAH). About 34 chemicals were found in over 90% of the total samples. Compared to their mothers during pregnancy, children had higher amounts of certain chemicals, like bisphenol S (BPS)—a chemical used in some hard plastics and synthetic fibers as a replacement for BPA—and pesticide-related compounds. On the other hand, mothers had higher levels of chemicals like triclosan and monoethyl phthalate (MEP), markers of exposure to chemicals found in some consumer products like soaps and cosmetics.

Certain groups of children, such as younger kids, later-born siblings, and those from families with fewer resources, were exposed to higher levels of chemicals.

 

What was the study's impact?

This study suggests that young children may be exposed to a variety of emerging and replacement chemicals that may affect their health later in life. Continued monitoring in larger populations of young children can help researchers better understand how these exposures affect children’s long-term health.

 

Who was involved?

The study included 201 children aged 2-4 years and their mothers recruited from six ECHO Cohort study sites across the United States.

 

What happened during the study?

Researchers collected urine samples from each child and their mother during pregnancy. These samples were analyzed for the levels of 111 different chemicals related to environmental exposures. The concentrations of these chemicals were compared between child and prenatal maternal samples. The researchers also examined social and environmental factors that may have influenced the concentration of each chemical in children's urine samples, such as race, ethnicity, maternal education, maternal age, 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?

Additional studies tracking early childhood exposures to a variety of contemporary and emerging chemicals could help researchers better understand the potential effects these exposures may have on children’s short and long-term health.

 

Where can I learn more?

Access the full journal article, titled “Exposures to Contemporary and Emerging Chemicals Among Children Aged 2-4 Years in the United States Environmental Influences on Child Health Outcomes (ECHO) Cohort,” in Environmental Science & Technology.

 

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

Published June 30, 2025

 

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Young Children May Be Exposed to a Variety of Emerging Chemicals Found in Some Consumer Products

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COVID-19 Pandemic May Have Altered Exposures to Environmental Chemicals, ECHO Study Finds

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COVID-19 Pandemic May Have Altered Exposures to Environmental Chemicals, ECHO Study Finds

Authors: Megan Romano, et al.

 

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health supported this research.

 

Why was this study needed?

The COVID-19 pandemic caused unprecedented disruptions in the daily lives of children and families worldwide. In the United States, recommendations to stay home and wear masks may have altered people's exposure to various potential endocrine-disrupting chemicals (EDCs). For example, changes in the use of certain consumer products, such as N-95 masks, and decreased exposure to air pollutants due to lockdown may have influenced these exposures. ECHO researchers wanted to learn whether exposures during pregnancy changed during the COVID-19 pandemic.

 

What were the study results?

During the COVID-19 pandemic, urinary levels of certain chemicals changed, reflecting shifts in exposure. Levels of specific polycyclic aromatic hydrocarbons (PAHs), which are air pollutants from car exhaust, fire smoke, and some grilled foods, decreased. Some synthetic phenols, used in plastics and disinfectants found in household cleaners and consumer products like mouthwashes, also showed a decline. However, levels increased of certain organophosphate esters (OPEs)—chemicals used in plastics, flame retardants, and cleaning agents, and more recently in surgical, KN95, and N95 masks. - The increase in these chemicals may be linked to the use of face masks during the pandemic. When people wore masks regularly, they may have unknowingly inhaled small amounts of these chemicals, leading to higher levels in their bodies. In contrast, urinary concentrations of chemicals commonly found in plastics, personal care products, and pesticides remained largely unchanged.

 

What was this study's impact?

The study highlighted how significant behavioral changes during the pandemic may have contributed to changes in exposures to harmful environmental chemicals.

 

Who was involved?

The study included 47 participants from three ECHO Cohort Study Sites who contributed urine samples before and during the COVID-19 pandemic.

 

What happened during the study?

Researchers collected urine samples from participants before (between October 2018 and February 2020) and during (between March 2020 and April 2021) the COVID-19 pandemic. They tested the samples for various chemicals.

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?

Researchers could continue tracking changes in chemical exposures and their potential health effects to better understand how these environmental exposures change over time, particularly during significant societal changes like the COVID-19 pandemic.

 

Where can I learn more?

Access the full journal article, titled “Changes in urinary concentrations of contemporary and emerging chemicals in commerce during the COVID-19 pandemic: Insights from the Environmental influences on Child Health Outcomes (ECHO) program,” in PLoS One.

 

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

Published January 24, 2025

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COVID-19 Pandemic May Have Altered Exposures to Environmental Chemicals, ECHO Study Finds

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Exposures and Pregnancy

Emily Oken: Using Cohort Studies to Understand Joint Effects of the Environment and Lifestyle on Health

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Using Cohort Studies to Understand Joint Effects of the Environment and Lifestyle on Health

Speaker:

Emily Oken

Department of Population Medicine at Harvard Pilgrim Health Care Inc

 

 

 

Speaker Bio: Dr. Oken was trained in internal medicine and pediatrics and is currently a Professor in the Department of Population Medicine at Harvard Medical School and the Harvard Pilgrim Health Care Institute, and in the Department of Nutrition at the Harvard School of Public Health.  Dr. Oken Directs the Division of Chronic Disease Research Across the Lifecourse within the Department of Population Medicine.  Her research focuses on the influences of nutrition and other environmental factors during pregnancy and early childhood on pregnancy outcomes as well as long-term maternal and child health, especially cardiometabolic health, cognitive development, asthma, and atopy.   Since 2016 she has led Project Viva, a pre-birth cohort study that has followed pregnant women and their children since 1999.  Project Viva is currently conducting in follow-up visits with teens aged 17-19 and their moms.  The team is doing a fantastic job weathering the challenges of transition to remote data collection.

 

Date: Wednesday, May 13, 1 to 2pm

Slides

Leo Trasande: Endocrine Disrupting Chemicals: A Costly Public Health Threat with Opportunities for Policy Prevention

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Endocrine Disrupting Chemicals: A Costly Public Health Threat with Opportunities for Policy Prevention

Speaker:

Leo Trasande, MD, MPP

NYU School of Medicine, Professor of Pediatrics

 

 

 

About the Speaker:
Leonardo Trasande, MD, MPP is a professor in the departments of Pediatrics, Environmental Medicine, and Public Health at New York University, and is a leader in children’s environmental health researcher. His research focuses on the roles of environmental exposures in childhood obesity, and on the economic costs of failing to address these environmental factors to prevent diseases in children proactively.

Dr. Trasande received his bachelors, medical, and public policy degrees from Harvard University. He also completed the Boston Combined Residency in Pediatrics and a legislative fellowship in the Office of Senator Hillary Rodham Clinton.

Outcome Areas: Obesity; Neurodevelopment

Date: Tuesday, October 15, 1 to 2pm

Slides