Author: Jodi Snare

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.

New ECHO Study Finds Link Between Prenatal Air Pollution Exposure and Behavior Scores in Young Children

Posted on by Jodi Snare

Exposure to air pollutants fine particulate matter (PM2.5) and nitrogen dioxide (NO2) during pregnancy was associated with slightly higher behavior problem scores in preschool-aged children, even when PM2.5 levels were below the current United States air quality standard, according to a new ECHO Cohort study led by Jiwon Oh, PhD, and Deborah Bennett, PhD, of the University of California, Davis.

Air pollution is common in many places, and pregnant women can be exposed to it where they live, work, and travel. Scientists think some air pollutants may affect a baby’s developing brain during pregnancy, which could later show up as differences in behavior. Using data from 8,370 pregnant women and their children from 28 ECHO Cohort Study Sites across 21 U.S. states and Puerto Rico, researchers looked at the association between exposures to common air pollutants like PM2.5, NO₂, and ozone (O3) during pregnancy and behavior problems in young children.

Key takeaways:

  • Exposure to PM5 and NO2 in air pollution during pregnancy was associated with modest increases in childhood behavior problems, including externalizing behaviors (e.g., acting out, aggression, attention problems) and internalizing behaviors (e.g., anxiety, withdrawal, emotional reactivity) in preschool-aged children (1.5–5 years).
  • Exposures in different “sensitive windows” during pregnancy showed different links to child behavior. First trimester PM5 exposure was associated with higher externalizing behavior scores. Second trimester PM2.5 exposure was associated with higher internalizing behavior scores. Third trimester NO₂ exposure was linked to higher internalizing and externalizing behavior scores.
  • Ozone (O₃) exposure was not significantly associated with child behavior scores overall.
  • Certain individual and community-level sources of stress like prenatal depression and childhood neighborhood opportunity (e.g., job opportunities, economic resources, socio-economic inequities, housing quality) influenced the association between prenatal exposure to air pollution and child behavior.

“Many ECHO pregnant women are exposed to PM2.5 levels that exceed the current U.S. air quality standard,” said Dr. Bennett. “Further investigations are needed to determine whether this standard is sufficiently protective of child neurodevelopment.”

Future studies can help researchers understand if prenatal air pollution exposure continues to show an association with children’s behavior beyond early childhood. Researchers can also explore how other factors, such as stress, access to healthcare, housing conditions, and other environmental exposures, might influence the association between prenatal air pollution exposure and children’s brain development.

This collaborative research, titled “Prenatal exposure to nitrogen dioxide, fine particulates, and ozone in relation to child behavior: The Environmental influences on Child Health Outcomes (ECHO) Cohort,” was published in Environmental Science & Technology.

ECHO Study Finds No Strong Overall Link Between Exposure to Gas Stoves, Mold, or Water Damage During Pregnancy and Birth Outcomes

Posted on by Jodi Snare

Having a gas stove, mildew or mold, or water damage in the home during pregnancy was not associated with shorter pregnancy duration or lower birth weight, according to a recent ECHO Cohort study led by Deborah Bennet, PhD, and Jiwon Oh, PhD, of University of California, Davis.

While outdoor air pollution has been linked to adverse birth outcomes such as preterm birth and low birth weight, less is known about the effects of common indoor household exposures during pregnancy such as gas stoves, mold or mildew, and water damage. These exposures can contribute to indoor air pollution or damp conditions that may affect maternal and fetal health.

Overall, the results of this study found no strong overall link between these household exposures and outcomes like preterm birth or birth weight, when looking at the full study population. Using kitchen ventilation, such as a hood or fan, also did not appear to change these results.

However, some differences were seen in certain groups. For example, mold or mildew and water damage were linked to a higher likelihood of early term birth (37-38 weeks) in homes built after 1980, and mold exposure was associated with a higher chance of preterm birth among mothers with higher education. Other patterns varied by race and ethnicity.

These findings suggest that indoor air quality during pregnancy may not have a strong association with birth outcomes overall, but that housing and social factors may influence how these exposures affect health.

“Although the presence of gas stoves, mold, or water damage in the home during pregnancy was not associated with adverse birth outcomes in this population-based study, frequent ventilation through windows or doors is recommended to reduce exposure to potentially harmful indoor air pollutants,” said Dr. Bennett.

Researchers say future studies could provide more details about indoor conditions, including how often gas stoves are used, how well homes are ventilated, and how severe mold or water damage may be.

This collaborative research, titled “Prenatal Exposure to Gas Stoves, Mold, and Water Damage: Associations With Gestational Duration and Fetal Growth in the ECHO Cohort,” is published in Environmental Pollution.

Fertility Challenges Associated with Small Differences in Children’s Neurodevelopment, NIH Study Finds

Posted on by Jodi Snare

Father and child playing

Difficulty conceiving a pregnancy may be associated with small differences in children’s learning and behavior, according to a new study funded by the Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health (NIH).

Neurodevelopmental differences in childhood, including behavioral concerns and conditions such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), can affect long-term health and well-being. As more families use fertility treatments, researchers are working to understand whether these treatments—or the underlying fertility challenges that preceded them—may be linked to children’s development. Previous studies have often been small or unable to separate the effects of infertility from the effects of treatment.

To address these gaps, researchers analyzed data from the ECHO Cohort, examining how fertility history and fertility treatments were related to children’s neurodevelopment. The study included 15,382 mother–child pairs from 44 study sites across the U.S., including Puerto Rico. Researchers combined survey data and medical records to categorize pregnancies by fertility history, including infertility diagnoses, fertility treatments, multiple miscarriages, and extended time trying to conceive. Children’s development between ages 2 and 10 was assessed using parent-completed questionnaires and reports of clinician diagnoses of ASD and ADHD.

In this study, children of parents with fertility challenges showed slightly higher behavior-problem scores, slightly more autism-like traits, and higher odds of an ASD diagnosis, even when conceived without fertility treatment. The study also found an association between children conceived using non–in vitro fertilization (IVF) fertility treatments had higher odds of ADHD compared with those conceived naturally. However, researchers did not find clear evidence that IVF itself was associated with neurodevelopmental outcomes.

Key takeaways include:

  • Parental fertility challenges were associated with small differences in children’s behavioral and developmental outcomes.
  • Conception using non-IVF fertility treatments was associated with higher odds of ADHD.
  • IVF was not clearly associated with neurodevelopmental outcomes in this study.

“This study contributes to the growing body of evidence indicating that infertility treatment itself is not independently associated with child neurodevelopment outcomes,” said ECHO researcher Linda Kahn, PhD, of NYU Langone Health. “Rather, it appears that the parents’ underlying fertility problems—whether stemming from genetic, environmental, or other influences—are likely driving these associations.”

This collaborative research, titled “Associations of subfecundity and infertility treatment with child neurodevelopment in ECHO,” is published in JAMA Network Open.

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, please contact  NIHKidsandEnvironment@od.nih.gov.

Connect With Us

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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.

Yearly Patterns of Rhinovirus Infection Consistent Over Three Decades

Posted on by Jodi Snare

Yearly circulations patterns of rhinovirus (RV)—the most common cause of the common cold—were remarkably consistent over three decades with certain types of rhinovirus found more often in infants and young children, according to a recent ECHO Cohort study led by Jo Wilson, MD of the University of Wisconsin School of Medicine and Public Health.

Some children—especially infants, toddlers, and children with asthma—can become seriously ill from a rhinovirus infection and may need hospital care. There are more than 160 different types of rhinoviruses, which has made it very difficult to develop prevention or treatment strategies. A relatively small group of rhinovirus types—about 15 to 20—account for about half of all the rhinoviruses circulating in each species, RV-A, RV-B and RV-C. Given the vast number of circulating rhinoviruses and the lack of rhinovirus surveillance programs, there has not been enough information for researchers to understand the circulation patterns of these viruses or which type are found most often in different age groups. To better understand the long‑term patterns of rhinovirus infections in children, researchers collected nearly 12,000 nasal samples from children across the United States, Finland, and Australia between 1997 and 2025.

Key Takeaways include:

  • Unlike other viruses like the flu or COVID‑19 that show dramatic changes in yearly circulation patterns, both the most common and rare rhinovirus types stayed remarkably consistent over three decades.
  • Certain rhinovirus types appeared more often in infants and young children, while a few others were common across all age groups.

The results of this study and additional studies can help researchers better understand which rhinovirus types are more commonly found in young children. This information could help guide the development of future strategies to prevent or treat rhinovirus infections.

This collaborative research, titled “Stability and Age-Specific Patterns of Rhinovirus Circulation in Children Observed Over Three Decades” is published in the Journal of Allergy and Clinical Immunology.

An NIH ECHO Program Transition

Posted on by Jodi Snare

I plan to retire from federal service on May 31, 2026. It is a singular privilege to serve as the inaugural Director of the NIH ECHO Program since its inception in July 2016. After almost 10 years, the ECHO Cohort and the ECHO IDeA States Pediatric Clinical Trials Network (ISPCTN) are mature, productive, and impactful. Today, ECHO is a leading source of evidence on the root causes and prevention of common chronic childhood conditions, and it is well positioned to expand its impact through continued rigorous, solution-oriented research, broad access to data and biospecimens, and translation of science into action.

While NIH actively searches for a new permanent director, ECHO Deputy Director Dr. S. Sonia Arteaga will continue to serve in a leadership role. Dr. Josh Denny will serve as acting director and Dr. Sara van Driest as senior advisor, each half time. Josh and Sara are, respectively, CEO and Director of Pediatrics for the All of Us Research Program, a sister program at NIH with a flagship adult cohort. Together, they will help advance alignment with the All of Us Research Program, but importantly, the programs will remain independent.

I encourage you to join the ECHO Symposium: Translating Science to Action on May 6, 2026, on the NIH campus in Bethesda, Maryland, and online. This free event will bring together researchers, policymakers, health professionals, advocates, and others to examine how chemical exposures affect child health and development—and how science is translated into meaningful action.

Thank you so much for your ongoing support for the ECHO Program, which is poised to substantially expand its impact on child health over the next few years.

 

Matthew Gillman, MD, SM
Director of the ECHO Program

Perceived Stress During Pregnancy Associated with Autism-related Traits in Children

Posted on by Jodi Snare

Higher perceived stress during pregnancy may be associated with greater severity of autism-related traits in children, according to a recent ECHO Cohort study led by Luke Grosvenor, PhD, of Kaiser Permanente Northern California.

Many mothers experience higher levels of stress and other mental health challenges during pregnancy. Previous studies have found that pregnancy stress may be associated with increased risk of autism spectrum disorder (ASD) in children, but these studies have mostly focused on the occurrence of isolated adverse or stressful events that occur in the mother’s life during pregnancy. Fewer studies have measured general perceived stress among mothers during pregnancy. To better understand whether this prenatal exposure may be associated with severity of autism-related traits in children, researchers collected information from over 4,000 mothers and their children enrolled in 20 ECHO Cohort Study Sites across the United States.

Key Takeaways include:

  • Higher perceived stress during pregnancy was associated with slightly more severe autism‑related traits in children.
  • At higher prenatal perceived stress levels, children showed slightly higher scores on tests measuring social and behavioral traits related to autism. Children whose mothers had either moderate or high categorical stress scored higher than those whose mothers reported low or no stress.
  • The link between pregnancy stress and autism‑related traits did not differ between boys and girls.
  • The relationship between prenatal stress and autism‑related traits remained consistent even when the researchers accounted for mothers’ co-occurring prenatal depressive symptoms.
  • Stress during pregnancy is normal and common to experience. While the results of this study indicate that there may be a small association between pregnancy stress and autism-related traits, they do not imply that stress during pregnancy causes autism spectrum disorder or autism-related traits to occur in children.

“This study provides evidence for small yet significant associations between higher prenatal perceived stress and greater severity of autism-related traits,” said Dr. Grosvenor. “These results could have implications for prenatal mental health screening and behavioral interventions aimed at improving child outcomes.”

Future studies could help researchers better understand the specific periods during pregnancy during which stress may have the greatest association with child health and development and how other related social and emotional factors may influence this effect.

This collaborative research, titled “Associations between Prenatal Perceived Stress and Child Autism-Related Traits in the ECHO Cohort,” is published in The Journal of Pediatrics.

Read the research summary.

 

Exposure to Flame-retardant Chemicals During Pregnancy Linked to Differences in Child Growth Patterns

Posted on by Jodi Snare

Prenatal exposure to certain flame-retardant chemicals may be associated with differences in how children grow from early childhood through age 10, according to a recent ECHO Cohort study by Anne P. Starling, PhD,  and Jessie P. Buckley, PhD, of UNC Chapel Hill, and Deborah Bennett, PhD, of University of California, Davis.

Organophosphate esters (OPEs) are widely used as flame retardants and plastic softeners in a variety of household and industrial products. Because these chemicals can be found in everyday environments, pregnant women are commonly exposed. While previous research has examined OPE exposure during pregnancy in relation to birth outcomes, less is known about whether prenatal exposure may be linked to children’s growth patterns beyond infancy.

To better understand these potential relationships, researchers measured nine chemical markers of OPE exposure in urine samples collected from pregnant participants. They then analyzed children’s weight and height measurements collected between ages 2 and 10 years and calculated body mass index (BMI). Using statistical models, the team examined whether prenatal OPE exposure was associated with differences in the rate of change in children’s weight, height, and BMI over time.

Researchers looked at 4,566 mother-child pairs from 14 ECHO Cohort Study Sites across the United States.

Key Takeaways :

  • Prenatal exposure to specific OPEs was associated with differences in child growth rates between ages 2 and 10.
  • Higher prenatal exposure to bis (1,3-dichloro-2-propyl) phosphate (BDCPP) was associated with faster increases in weight and height during early childhood (ages 2–5).
  • In mid-childhood (ages 6–10), higher prenatal exposure to diphenyl phosphate (DPHP) was associated with faster increases in BMI and weight.
  • Prenatal exposure to bis(1-chloro-2-propyl) phosphate (BCPP) was associated with slower growth across multiple periods.
  • Some associations differed by child sex and by maternal pre-pregnancy body mass index.

“This work increases our understanding of the potential long-term effects on child health from typical levels of exposure to these chemicals during pregnancy. The results may inform future guidance on the production and use of OPEs,” said Dr. Starling.

Additional research could help clarify the biological mechanisms involved and explore whether reducing exposure during pregnancy could support long-term child health.

This collaborative research, titled “Gestational exposure to organophosphate ester flame retardants and child growth in weight, height, and body mass index at age 2-10 years: the Environmental influences on Child Health Outcomes Program,” is published in Environmental Research.

Prenatal Smoking Associated with Higher Risk of Mental Health Challenges in Children

Posted on by Jodi Snare

Mother and toddler laughingChildren exposed to maternal smoking before birth are more likely to experience behavioral and mental health challenges, according to a large study funded by the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) Program.

While previous research had linked prenatal smoking to acting out or rule-breaking, it was less clear whether smoking during pregnancy also affects broader mental health outcomes and whether effects differ by sex.  The new study sheds light on these questions, examining thousands of children across the U.S. and identifying periods when exposure may be most impactful.

“These findings show that prenatal nicotine exposure can affect more than just acting-out types of behavior problems—it can influence children’s overall mental health and experiences of both emotional and behavioral problems at the same time,” said Kristine Marceau, PhD, of Purdue University. “Understanding when kids are most vulnerable can help families and healthcare providers provide support at the right time.”

Researchers analyzed data from 16,335 children ages 1 to 18 from 55 ECHO Cohort Study Sites. Behavioral assessments measured emotional and behavioral symptoms using standardized questionnaires.

Key Findings

  • Widespread Impact: Children exposed to prenatal smoking were more likely to have multiple mental health or behavioral symptoms at the same time.
  • Critical Windows: The strongest effects appeared in early childhood (under age 7) and early puberty (ages 9–12).
  • Similar Effects for Boys and Girls: Both sexes were affected in comparable ways, with slightly higher symptom levels in boys only at ages 13–14.
  • Independent of Family Background: Associations persisted even after considering family history and other environmental factors, such as maternal age, education, and additional substance exposures.

Future studies could take a closer look at the timing, amount, and frequency of smoking during pregnancy. Researchers could also work to better understand which effects are due to smoking itself—rather than other family factors—and how nicotine and other chemicals in smoke may affect how children grow and develop.

This collaborative research, titled “Prenatal Smoking and Child Psychopathology Associations by Age and Sex in the ECHO Cohort,” is published in Development and Psychopathology.

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

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.

Prenatal Stress and Maternal Adverse Childhood Experiences Linked to Higher Risk of Child Mental Health Problems

Posted on by Jodi Snare

Stress during pregnancy and a mom’s own adverse childhood experiences (ACEs) may be associated with higher risk of mental health problems for their children, according to a recent ECHO Cohort study led by Shaikh Ahmad, PhD, Alexandra Sullivan, PhD, and Nicole Bush, PhD of University of California, San Francisco, and Marie Churchill, MS and Rosa Crum, MD, MHS of Johns Hopkins Bloomberg School of Public Health.

The global rise in pediatric mental health problems has highlighted the importance of identifying factors that may affect children’s mental health. Previous research has suggested that maternal stress—both adverse experiences during the mother’s own childhood and stress during pregnancy—may affect child mental health. To better understand how these exposures affect child mental health, researchers collected information from over 6,000 mothers and their children enrolled in 34 ECHO Cohort Study Sites across the United States.

Key Takeaways include:

  • Mothers’ own ACEs and experiences of stress during pregnancy were each independently associated with a higher risk of mental health problems in their children, suggesting that maternal stressors during each period may have contributed to the child’s risk in a potentially accumulative manner.
  • These effects on children included both internalizing (e.g., anxiety, depression) and externalizing (e.g., ADHD, behavior problems) mental health issues.
  • The effects of maternal ACEs and pregnancy stress on child mental health problems were similar for boys and girls and were seen throughout childhood and adolescence.

“Using a large and diverse sample, this study highlights the potential two-generational benefits of early screening and intervention related to maternal stress and adversity—not only in improving maternal health, but also in reducing mental health problems in offspring,” said Dr. Ahmad.

Additional research could help researchers identify other factors that may influence the risk of child mental health problems (e.g., paternal ACEs) and factors that could improve support for pregnant women.

This collaborative research, titled “Maternal Adverse Childhood Experiences and Prenatal Stress: Intergenerational Transmission and Offspring Mental Health in the ECHO Cohort,” is published in Psychological Medicine.

Read the research summary.