Press Releases

Prenatal Exposure to Organophosphate Pesticides Not Associated with Autism-Related Traits in Children in Large NIH Study

Posted on by Jodi Snare

Pregnant mom at farmer's market

Exposure during pregnancy to a common type of pesticide was not linked to autism-related traits in children, according to a new study funded by the National Institutes of Health’s (NIH) Environmental influences on Child Health Outcomes (ECHO) Program.

The findings suggest that, at the relatively low levels of exposure observed in the study, these pesticides may not be associated with autism-related traits during childhood.

Organophosphate pesticides are chemicals used to kill insects. People can come into contact with them through food, especially non-organic fruits and vegetables. Earlier studies on whether exposure to these chemicals before birth suggest that they affect children’s brain and behavioral development and are consistently associated with cognitive challenges, and attention-deficit/hyperactivity disorder (ADHD). However, studies investigating their connection to Autism Spectrum Disorder (ASD) and related traits have had mixed results. Many of those studies included fewer families or looked at groups with higher exposure levels. ECHO Cohort researchers wanted to know whether these pesticides were linked to autism-related traits in a large and geographically diverse group of families across the United States.

Led by Haleigh M. Cavalier, MPH, PhD, of Columbia Mailman School of Public Health, the study included 3,339 mother-child pairs from 20 ECHO Cohort Study Sites across the country. Researchers tested urine samples collected during pregnancy for markers of organophosphate pesticide exposure. They then looked for associations between those markers and children’s scores on a standard questionnaire used to measure autism-related social and behavioral traits.

After accounting for other factors that can affect child development, researchers found no link between higher prenatal pesticide exposure and higher autism-related trait scores. The results were similar when researchers looked at girls and boys separately, focused on children with higher scores on questionnaires measuring autism-related traits, and considered available information about mothers’ diets.

"While we know that that organophosphate pesticides can harm the developing brain, they were not a major driver of characteristics seen in autism at the relatively low exposure levels we observed,” said Dr. Cavalier.

“These results should not be interpreted to mean that such pesticides are safe, nor do they rule out autism-related risks at higher exposures or among more vulnerable groups.”

Because diet can affect both pesticide exposure and child development, researchers also looked at whether diet changed the results. Including diet information shifted some estimates, suggesting diet may have influenced some of the patterns seen in the study. However, those shifts did not change the overall conclusion.

The findings do not address all possible health effects of pesticide exposure. Instead, they point to the need for better ways to measure exposure, more attention to highly exposed or potentially vulnerable populations, and continued research on ways to reduce pesticide exposure.

Future studies should continue to consider diet quality and look more closely at exposure during specific pregnancy stages, pesticide and other chemical mixtures, higher-exposure settings, and genetic factors that may make some children more susceptible.

This collaborative research was published in JAMA Pediatrics.

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

Media Contacts

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

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

Connect With Us

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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.

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Higher Fluoride Levels in Public Drinking Water During Pregnancy May Be Linked to Differences in Children’s Cognition Scores, NIH-Funded Study Finds

Posted on by Jodi Snare

Pregnant woman having a glass of water

Associations appeared when fluoride levels in neighborhood drinking water were close to or above current U.S. recommended levels.

Pregnant mothers who lived in neighborhoods where public drinking water fluoride levels were near or above the current U.S. recommended levels, tended to have children who scored lower on tests of fluid reasoning as fluoride levels increased, according to a new study supported by the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) Program.

Fluoride occurs naturally in some water sources and is commonly added to public water systems to help prevent cavities. The paper’s authors note that a recent National Toxicology Program review examined evidence linking fluoride exposure levels above 1,500 micrograms per liter in drinking water with lower IQ scores in children. However, most U.S. public water systems have lower fluoride levels, and questions remain about associations at lower levels typically found in the United States.

ECHO researchers looked at whether fluoride levels in public drinking water during pregnancy were related to cognitive scores assessed during childhood.

"This study addresses an important gap by evaluating prenatal water fluoride and child cognition in a large U.S. sample," said lead author Katrina Simon, PhD, of Columbia University Mailman School of Public Health. "Findings from this work offer evidence that can inform ongoing guidance aimed at supporting children's development."

Researchers reported that children whose mothers had higher estimated fluoride levels in public drinking water during pregnancy tended to score lower on tests of fluid cognition that include problem-solving, memory, attention, and the ability to adapt to new information. Higher water fluoride levels were only linked to lower fluid cognition scores when water fluoride levels were near and above 675 micrograms per liter, which is close to the current U.S. Public Health Service recommended level of 700 micrograms, or 0.7 milligrams, per liter for fluoridated water. The current regulatory level set by EPA is higher at 4,000 micrograms per liter. Above 675 micrograms per liter, each 500 micrograms per liter increase in fluoride was associated with an average 3.36-point lower score on the standardized fluid cognition scale.

Researchers also found that the relationship between prenatal fluoride levels and cognition was specific to fluid cognition. Importantly, the study did not identify a link between fluoride and crystallized cognition, which includes learned knowledge such as vocabulary, across all ages.

In addition, the associations appeared stronger when cognition was assessed at a younger age. Children younger than 7 years of age showed larger differences in cognition scores associated with higher prenatal fluoride exposure compared to older children. Additional research is needed to better understand these age-related findings.

The study included 2,514 children born between 2006 and 2019 who completed cognitive testing between ages 3 and 17.

To estimate prenatal water fluoride exposure, researchers linked publicly available drinking water fluoride measurements to residential address information collected during pregnancy from ECHO participants. The study focused specifically on fluoride levels in public drinking water systems and did not measure total fluoride exposure from all possible sources, such as toothpaste, tea, foods, supplements, bottled water, or private wells.

Researchers then compared these estimates with children's performance on NIH Toolbox cognition assessments, while accounting for factors such as parental education, parental age, prenatal tobacco exposure, child sex, season of conception, and neighborhood characteristics.

“Because our study used fluoride measurements from public water systems that are collected as part of routine drinking water monitoring, the findings may help inform future evaluations of public drinking water guidelines,” said co-senior author Anne Nigra, PhD, also of Columbia University Mailman School of Public Health.

Community water fluoridation has long been used as a public health measure intended to reduce tooth decay. The current study does not evaluate the overall benefits and risks of community water fluoridation

“This study adds to a large body of work that looks at how early exposure to environmental contaminants may be associated with the development of the thinking and learning processes that are important for children’s developmental outcomes,” said co-senior author Amy Margolis, PhD, of The Ohio State University Wexner Medical Center and College of Medicine. “Continuing to study fluoride and other exposures will be integral in best supporting children’s environmental health and well-being.”

The researchers emphasize that this was an observational study. The findings demonstrate an association between prenatal fluoride exposure and children's cognition, but they do not prove that fluoride caused differences in cognitive performance.

The authors noted that future research could focus on when children may be most sensitive to fluoride exposure and examine both potential developmental risks and dental health benefits to better understand relationships between fluoride exposure and child health.

This collaborative research was published in the American Journal of Epidemiology.

Simon KR, Bloomquist TR, Rajeev T, Hernandez A, Kulali S, Burjak M, Kress AM, Palmore M, Akbaryan A, Sanchez TR, Ornelas Van Horne Y, Shin HM, Goin DE, Tamayo-Ortiz M, Patel GH, Shuffrey LC, Ghassabian A, Karagas MR, Leventhal L, Fry RC, Miller RL, Herbstman J, Morales S, Margolis AE, Nigra AE. Prenatal exposure to fluoride in public water and child cognition in the US ECHO Cohort, 2006-2019. 2026. American Journal of Epidemiology. https://doi.org/10.1093/aje/kwag186

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

Media Contacts

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

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

Connect With Us

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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.

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Higher Blood Levels of Certain Metals During Pregnancy Associated with Autism-Related Traits in Children

Posted on by Jodi Snare

Pregnant woman

Higher levels of certain metals in mothers’ blood during pregnancy—including lead, mercury, and cadmium—were associated with autism-related traits in children, and higher levels of cadmium were associated with higher odds of an ASD diagnosis, according to a study funded by the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) Program.

Lead, mercury, and cadmium are metals that people may be exposed to through sources such as food, air, water, tobacco smoke, and some consumer products. During pregnancy, some metals can cross the placenta and reach the developing fetus. Previous studies have suggested possible links between prenatal metal exposure and ASD, but findings have been mixed, and many studies have examined one exposure at a time rather than the combined effects of multiple metals.

In this study, researchers analyzed data from mother-child pairs enrolled in the ECHO Cohort. They found that higher prenatal blood levels of lead and mercury were associated with higher scores on the Social Responsiveness Scale, Second Edition (SRS‑2), a caregiver-reported measure of social and behavioral traits related to autism. Higher blood cadmium levels were associated with higher odds of an ASD diagnosis.

When researchers looked at the metals together, higher combined levels of arsenic, cadmium, mercury, and lead were also associated with differences in autism-related behaviors, particularly in areas related to social functioning. Most metals measured in urine were not associated with these outcomes after accounting for other factors, although one metal (barium) showed differences by child sex that may warrant further study.

“We found that higher prenatal levels of metals—including lead, mercury, and cadmium—both individually and in combination, were associated with a higher likelihood of autism diagnosis and greater levels of autism-related behaviors, even at concentrations not typically considered elevated,” said Pi-I Debby Lin, ScD, of Harvard Pilgrim Health Care Institute. “These findings underscore the importance of increasing awareness of environmental exposures and strengthening approaches to screening during pregnancy, while continuing to evaluate what levels of exposure may be considered safe during this critical window of development.”

The study included 479 mother-child pairs with prenatal blood metal measurements and 482 pairs with prenatal urine metal measurements. Mothers provided samples during pregnancy, and researchers later compared those measurements with children’s SRS‑2 scores and ASD diagnoses when available. The analyses accounted for factors such as study site, maternal age, income, education, smoking exposure, and child sex.

The study, “Associations of prenatal metal exposures with autism-related outcomes in the ECHO Cohort,” was published in Environmental Epidemiology.

Media Contacts

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

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

Connect With Us

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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.

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

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

Posted on by Jodi Snare

Young mother eating and reading book at home

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Media Contacts

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

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

Connect With Us

echo connector

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

To receive the ECHO Connector through email, subscribe here.

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

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

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 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.

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

Housing Conditions and Outdoor Air Pollution Together Affect Children’s Asthma Risk, New ECHO Study Shows

Posted on by Jodi Snare

Children growing up in homes with water damage or dampness and exposed to higher levels of outdoor air pollution during early childhood face a greater risk of developing asthma, according to new research supported by the NIH’s Environmental influences on Child Health Outcomes (ECHO) Program. The large multisite study found that early-life exposure to fine particulate matter (PM2.5) and indoor housing problems each independently raised asthma risk, while having a dog during infancy was linked to reduced risk.

Asthma affects millions of U.S. children, yet the environmental origins of the disease are complex. While previous research has tended to study exposures such as pollution or indoor allergens separately, this study shows that evaluating them together offers a more accurate picture of children’s risk. The ECHO Program, which brings together data from diverse U.S. populations, made this integrated analysis possible.

Drawing on data from 6,413 children across nine U.S. ECHO Study Sites, the research provides one of the clearest looks yet at how multiple early-life environmental factors interact to influence childhood asthma. The findings underscore the importance of assessing both indoor and outdoor environments together, rather than in isolation — an approach that prior studies often could not address due to limited sample sizes.

“Our research shows that to truly understand and prevent childhood asthma, we need to look at a child’s full environment—both the air they breathe outside and the conditions inside their home,” said Akihiro Shiroshita, a study author from Vanderbilt University School of Medicine. “Considering these factors together gives us a much clearer picture of what puts children at risk and how we can better protect them.”

Key Findings

  • Outdoor air pollution matters: Higher early life exposure to PM2.5 was associated with increased asthma risk.
  • Indoor environments matter too: Home dampness or water damage independently raised asthma risk, even after accounting for pollution exposure.
  • Pets may offer protection: Having a dog in the home during infancy was linked to a lower risk of developing asthma.
  • Large, diverse dataset: The study combines data from multiple U.S. ECHO Study Sites, offering a comprehensive view of environmental impacts on children’s respiratory health.

Researchers evaluated children’s exposure to PM2.5 during the first three years of life and combined that information with detailed data on early life housing conditions — including water damage, dampness, pet exposure, and dust mites. Childhood asthma was identified based on caregiver reports or physician diagnosis between birth and age five. The analysis also controlled for family and neighborhood factors to isolate the effects of environmental exposures.

The findings signal the need for additional research into how indoor and outdoor exposures interact and how early life interventions could help reduce asthma risk in children nationwide.

This collaborative research was published in Environmental Epidemiology.

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

Media Contacts

For information or to request an interview, contact 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 and Early-Life Pollution Exposures May Influence Childhood Blood Pressure Patterns, ECHO Study Finds

Posted on by Jodi Snare

A child’s blood pressure may be influenced by exposure to air pollution before and shortly after birth, according to a new study from the NIH-funded Environmental influences on Child Health Outcomes (ECHO) Program. The study focused on fine particulate matter (PM2.5) and nitrogen dioxide (NO2), common pollutants from vehicles, power plants, and other industrial sources.

High blood pressure in children is becoming more common worldwide and can lead to long-term health problems, including heart disease and impaired kidney function. Over the past two decades, childhood hypertension has increased by nearly 80 percent, particularly in countries with higher obesity rates, such as the United States. Because the roots of adult hypertension often begin in childhood, ECHO researchers examined whether early exposure to outdoor air pollution may influence blood pressure in children.

Air pollutants such as PM2.5 and NO2 are known contributors to cardiovascular disease in adults, but their effects on children’s blood pressure are less well understood. Previous studies have produced mixed results and were often limited to single locations. This ECHO study leveraged data from multiple cohort sites across the United States to better clarify these associations.

Researchers analyzed data from 4,863 children ages 5 to 12 from 20 ECHO Cohort Study Sites. They estimated outdoor air pollution exposure at participants’ home addresses during each trimester of pregnancy, across the full pregnancy, and during the child’s first two years of life. Children’s blood pressure was measured during study visits and compared with typical values for children of the same age, sex, and height. Blood pressure was considered high if it fell within the top 10 percent of these values.

Key Findings

  • PM2.5 exposure and higher blood pressure: Children who were exposed to higher levels of PM2.5 before and after birth had higher blood pressure on average between ages 5 and 12.
  • Early pregnancy as a sensitive period: Higher PM2.5 exposure during the first trimester was associated with a more pronounced systolic blood pressure and a greater likelihood of high blood pressure in childhood, indicating that early pregnancy may be a particularly sensitive period.
  • Unexpected findings for NO2: Higher maternal exposure to NO2 during pregnancy was associated with slightly lower blood pressure in children. This association was strongest during mid- to late pregnancy, particularly the second trimester, and was not linked to an increased risk of high blood pressure.
  • Timing matters: The results suggest that the timing of pollution exposure during pregnancy may be important for understanding its impact on children’s cardiovascular health.

“These findings add to growing evidence that early-life exposure to fine particulate air pollution may affect children’s cardiometabolic health, even at relatively low levels,” said study author Yu Ni, PhD, of San Diego State University. “The unexpected findings related to nitrogen dioxide suggest that more research is needed to understand how this type of air pollution may affect children’s developing bodies, as well as whether other environmental factors could be playing a role, such as transportation noise.”

This collaborative research was published in Environmental Research.

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.

Wildfire Smoke Exposure During Pregnancy Linked to Higher Risk of Preterm Birth, ECHO Study Finds

Posted on by Jodi Snare

Study highlights increased risk, especially in Western states and during intense smoke events

Exposure to wildfire smoke during pregnancy was associated with a higher risk of preterm birth, especially in the Western United States and during periods of intense or prolonged smoke, according to a study funded by the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) Program.

Wildfires are becoming more frequent and severe, raising concerns about their impact on public health. While previous studies suggested a link between wildfire smoke and preterm birth, ECHO’s research built on this by studying a diverse population from prospective cohort sites nationwide. Researchers also looked closely at the role of exposure intensity, duration, and timing.

“Our study adds to growing evidence that wildfire smoke is a concern for maternal and child health. Incorporating wildfire smoke considerations into prenatal care and public health guidance could help expecting parents protect themselves during smoke events, especially in areas where wildfires are common,” said Allison Sherris, PhD, of the University of Washington.

Researchers analyzed data from over 20,000 births between 2006 and 2020 at 30 study sites across the U.S. They matched daily levels of air pollution from wildfire smoke (fine particulate matter, or PM2.5) to each participant’s home address during pregnancy. They tracked both the average amount of smoke and the number of “smoke days,” as well as “smoke waves”—stretches of consecutive days with high smoke levels.

The team used statistical methods to compare pregnancies week by week and adjusted for many factors, including maternal age, race, ethnicity, neighborhood poverty, season of conception, birth year, and more.

Key Findings

  • Widespread Exposure: Nearly all pregnant participants (99.2%) experienced at least one day of wildfire smoke, with an average of 22 smoke days during pregnancy.
  • Preterm Birth Risk: The overall rate of preterm birth was 8.4%, with higher rates among Black (11.7%) and American Indian or Alaska Native (13.5%) participants compared to White (7.6%) and Asian, Native Hawaiian, or Pacific Islander (8.0%) participants.
  • Link Between Smoke and Preterm Birth: For every 1 microgram per cubic meter (µg/m³) increase in average wildfire PM2.5 during pregnancy, the odds of preterm birth increased by about 7%. The association was even stronger in the Western U.S., where wildfire smoke is more intense and frequent.
  • Intensity and Duration Matter: The risk of preterm birth was higher with more intense smoke and longer-lasting smoke events. The strongest associations were seen for mid-pregnancy exposure to lower levels of smoke and late-pregnancy exposure to high-intensity smoke days.
  • Critical Windows of Vulnerability: Certain periods during pregnancy—especially mid-pregnancy for lower-intensity smoke and late pregnancy for high-intensity smoke—were linked to the greatest risk increases for preterm birth.

“Preterm birth has strong implications for future child health. Better understanding of how to prevent preterm birth will pay off as a healthier population into the future,” said Catherine Karr, MD, PhD, of the University of Washington.

The study points to the need for more research on why some regions or groups may be more affected, how wildfire smoke combines with other risks like extreme heat, and which prevention strategies work best. It also highlights the importance of public health agencies and healthcare providers offering ways to help keep pregnant people safe during wildfire events.

This collaborative research was published in The Lancet Planetary Health.

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

Media Contacts

For information or to request an interview, contact 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.

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Toddlers Showed Slightly Fewer Behavioral Problems During COVID-19 Pandemic, NIH Study Finds

Posted on by Jodi Snare

Toddlers assessed during the COVID-19 pandemic had slightly fewer emotional and behavioral problems compared to children assessed before the pandemic, suggesting some toddlers may have shown resilience during this time. This finding comes from a study of over 3,000 children across the United States using data from the Environmental influences on Child Health Outcomes (ECHO) Cohort Consortium collected between September 2009 and July 2023.

The COVID-19 pandemic disrupted family patterns and children’s environments, both critical for early brain development and well-being. While earlier research raised concerns about infants born during the pandemic, there is limited information about how toddlers’ emotional and behavioral health might have been affected.

To explore this, the study examined data from 3,438 toddlers (average age of 2 years) across the U.S. and Puerto Rico. Researchers used the Preschool Child Behavior Checklist (CBCL), a parent-reported measure of child behavior and emotions, to compare children assessed before and during the pandemic.

Children were grouped based on when they were born and when their behavior was assessed: before the pandemic, born before but assessed after March 2020, or both born and assessed during the pandemic. Parents completed the CBCL, which asks about behaviors such as anxiety, sadness, and aggression. These reports helped researchers understand how growing up during the pandemic might have influenced toddler emotional and behavioral health.

Key findings include:

  • Children who experienced the pandemic had significantly lower scores for internalizing problems (such as anxiety and sadness) and externalizing problems (such as aggression or hyperactivity) compared to children assessed before the pandemic.
  • Internalizing problem scores were about 1.5 to 2 points lower, and externalizing problem scores were about 1.7 to 3.2 points lower than those born and assessed before the onset of the pandemic.
  • Although the differences were small, they were consistent. The associations were stronger among children whose mothers did not have a bachelor’s degree.

“Our findings suggest that even during periods of widespread pandemic-related disruption, toddler-aged children may have experienced opportunities for resilience,” said study author Anahid Akbaryan, a Research Associate at NYU Grossman School of Medicine. “Future research should explore within-home factors that may have supported child mental health outcomes during this time, such as consistent caregiving routines, household stability, and positive parental coping strategies to identify potential protective influences during times of instability.”

Study author Lauren Shuffrey, PhD, of NYU Grossman School of Medicine, added, “These findings suggest that some families may have adapted in ways that buffered young children from behavioral challenges during the pandemic, highlighting the importance of identifying and strengthening those protective supports.”

The researchers emphasized that further studies are needed to identify these protective factors and develop strategies to help families support child well-being during and after times of global disruptions.

This collaborative research 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, 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 connectorCheck 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.