low birthweight

Early‑Pregnancy Exposure to Fine Particulate Air Pollution Linked to Lower Birthweight in New ECHO Study

Posted on by Jodi Snare

Exposure to fine particulate matter (PM2.5)—tiny inhalable particles found in air pollution—during the earliest weeks of pregnancy was associated with babies being slightly smaller for gestational age, according to a new ECHO Cohort study led by Whitney Cowell, MPH, PhD, of NYU Langone Health.

Low birthweight is a known risk factor for a range of health issues in infancy and later life. Prior studies have shown links between PM2.5 exposure and birth outcomes, but many examined average exposure over time, leaving uncertainty about which specific weeks may be most harmful. This study aimed to pinpoint sensitive windows in early pregnancy when exposure may have the greatest impact.

Using data from 16,868 pregnant women at ECHO Cohort sites across the United States, researchers estimated weekly PM2.5 exposure during pregnancy and analyzed how it related to birthweight. They also evaluated whether associations varied by infant sex, parent race and ethnicity, or region the mother lived in during pregnancy.

Key takeaways:

  • Higher PM5 exposure during early pregnancy—particularly weeks 1–5—was associated with lower birthweight.
  • Male newborns appeared more sensitive to these early‑pregnancy exposures than female newborns.
  • Effects varied by U.S. region, with stronger associations in the Northeast, South, and Midwest, and weaker effects in the West—likely due to differences in particle types.

“The findings from this study support the need to periodically reevaluate National Ambient Air Quality Standards to ensure recommendations protect the health of the most sensitive subgroups, including pregnant women and fetuses,” said study author Dr. Cowell.

Understanding precisely when fetuses are most vulnerable to air pollution can help guide public health strategies and shape future investigations into biological mechanisms. The findings highlight the need for closer examination of pollutant composition, maternal factors, and other influences—such as diet or lifestyle—that may modify risk.

This collaborative research, titled “PM2.5 in relation to birthweight: exploring windows of susceptibility in the ECHO Cohort,” was published in JAMA Network Open.

Exposure to Fine Particulate Air Pollution in Early Pregnancy Linked to Lower Birth Weight, ECHO Study Finds

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Exposure to Fine Particulate Air Pollution in Early Pregnancy Linked to Lower Birth Weight, ECHO Study Finds

Authors: Whitney Cowell, 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?

Babies born with low birth weight are at a higher risk for health problems both at birth and later in life. Prior research has shown that exposure to fine particulate matter (PM2.5)—very small inhalable particles found in air pollution—during pregnancy can negatively affect birth weight. Many past studies examined average exposure over pregnancy, which may miss specific windows when the baby is most sensitive. The goal of this study was to identify the specific weeks in pregnancy when babies are most vulnerable to PM2.5 exposure.

 

What were the study results?

Exposure to PM2.5 during pregnancy was associated with lower birth weight for gestational age, particularly when exposure occurred in the early weeks of pregnancy (weeks 1–5). Male newborns appeared more sensitive to exposure than females. The study also found regional differences, with stronger associations observed in the Northeast, South, and Midwest. This may relate to differences in the types of particles found in the air in these regions.

 

What was this study's impact?

This study gives us a clearer picture of when during pregnancy air pollution may be most harmful to a baby’s growth. Understanding these sensitive time periods can inform future research on what’s happening in the body during those weeks and why pollution may have a bigger impact during those times.

 

Who was involved?

The study included 16,868 pregnant participants from the ECHO Cohort, spanning 50 sites across the United States.

 

What happened during the study?

Researchers applied computer models to estimate pregnant participants' weekly exposure to PM2.5 throughout their pregnancies. Birth weight was recorded at the time of delivery and then standardized using national growth charts to account for variations in gestational age (length of pregnancy).  Analysts used statistical methods to identify how overall and week-specific PM2.5 exposure related to birthweight. These methods also tested whether the impact of PM2.5 differed by the baby’s sex, race or ethnicity of the parents, or the region of the country the mother lived in during pregnancy.

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 explain how different types and sizes of pollution particles affect baby’s growth. Additional research could also help identify the periods of pregnancy when reducing exposure would have the greatest impact.

 

Where can I learn more?

Access the full journal article, titled “PM2.5 in relation to birth weight: exploring windows of susceptibility 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 December 1, 2025

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Exposure to Fine Particulate Air Pollution in Early Pregnancy Linked to Lower Birth Weight, ECHO Study Finds

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Pre-, Peri-, and Postnatal

Pregnancy Diet Patterns and their Associations with Birth Outcomes Differ Across Racial and Ethnic Groups

Posted on by Jodi Snare

Dietary patterns during pregnancy can affect maternal blood sugar levels and birth outcomes, with important differences depending on racial and ethnic backgrounds, according to a recent ECHO Cohort study led by Luis E. Maldonado, PhD, MPH, of the University of Southern California.

Which combination of foods most influences blood sugar and birth outcomes during pregnancy remains unclear, especially across different racial and ethnic groups. Studying these differences is important because, although diet is known to affect birth outcomes, variations in dietary patterns may help explain disparities—for example, Hispanic women in the U.S. face higher rates of preterm birth and low birthweight compared to non-Hispanic White women.

“Our findings show it’s important to look at how diet affects birth outcomes in different racial and ethnic groups separately, especially in diverse communities,” said Dr. Maldonado. “Combining all racial and ethnic groups into one might hide important differences in how diet relates to birth outcomes for each group.”

Researchers analyzed data from over 980 pregnant women—420 Hispanic and 564 non-Hispanic White participants—from two ECHO Cohort study sites. Their aim was to identify how different combinations of food related to blood sugar and birth outcomes such as preterm birth and low birthweight.

Key takeaways

  • Diets high in refined grains (like white bread or white rice) and low in whole grains were linked to babies being born earlier, smaller, or with low birthweight.
  • Analyzing dietary patterns within specific racial and ethnic groups revealed stronger associations with negative birth outcomes than when looking at the combined group.
  • Among non-Hispanic White women, whole grains were most strongly associated with better blood sugar control.
  • Fruit was linked to higher blood sugar levels among Hispanic participants.
  • Solid fats and nuts and seeds were associated with lower blood sugar levels in both groups.

The study underscores the value of considering dietary patterns separately within racial and ethnic groups to better understand how diet affects pregnancy outcomes. Future research can build on these findings by continuing to explore culturally relevant dietary patterns in diverse populations, helping uncover associations that may be missed in broader, combined analyses.

This collaborative research, titled “Racial/Ethnic-Derived Maternal Diets Predict Birth Outcomes Better than a Diet Derived from a Combined Sample among Hispanic/Latina and non-Hispanic White Pregnant Individuals in the ECHO Cohort,” in Nutrition.

Adverse Birth Outcomes May be Associated with Arsenic Levels in Public Drinking Water

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Adverse Birth Outcomes May be Associated with Arsenic Levels in Public Drinking Water

Authors: Anne Nigra, 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?

Regulated U.S. public drinking water is a source of exposure to arsenic. Because arsenic occurs naturally, water that comes in contact with certain rocks and soils may contain it. Contamination from various industrial processes also contributes to increased levels of arsenic in some areas. Prenatal exposure to arsenic has been associated with adverse birth outcomes, including preterm birth and low birthweight. Researchers studied how arsenic in public drinking water—at levels below the federal limit—may affect birth outcomes in the ECHO Cohort. Previous evidence has been limited to private well exposures, studies using urinary biomarkers, and single-site studies with limited racial, ethnic, and geographic diversity.

 

What were the study results?

The study found that when pregnant women lived in areas with publicly reported high levels of arsenic in public drinking water, even at levels below the current federal safety standard of 10 micrograms per liter, their babies were more likely to be born with low birthweight (weighing less than 5 lbs 8 oz) or are small for their gestational age (smaller than babies born at the same number of weeks of pregnancy). These patterns were seen across several racial and ethnic groups, including White, Black, and Hispanic/Latino families. For example, babies born to Hispanic/Latino parents were about 40% more likely to have low birthweight with just a 5 microgram-per-liter increase in water arsenic. The study also found that babies born to Black parents had higher risks of being born early, with low birthweight, or smaller for their gestational age. Similar risks were observed among babies born to American Indian, Alaskan Native, Native Hawaiian, and Pacific Islander parents.

 

What was this study's impact?

The study shows that even low levels of arsenic in public drinking water may increase the risk of babies being born too early, too small, or underweight.

 

Who was involved?

Participants included 13,998 birthing mother-infant pairs from the ECHO Cohort.

 

What happened during the study?

Researchers estimated how much arsenic people were exposed to through public drinking water during pregnancy by combining water quality data with where each person lived each month. They then looked at whether that exposure was linked to outcomes like being born early (preterm birth), having a low birthweight, or being small for their gestational age.

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 help researchers understand how current efforts to reduce arsenic in drinking water are working—whether those efforts happen across the country, in local communities, in homes, or for individuals. Studies could also help identify where arsenic levels are highest, which may support ongoing work to make sure communities have safe drinking water.

 

Where can I learn more?

Access the full journal article, titled “Public water arsenic and birth outcomes in the Environmental influences on Child Health Outcomes 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 16, 2025

 

Access the associated press release.

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Adverse Birth Outcomes May be Associated with Arsenic Levels in Public Drinking Water

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Pre-, Peri-, and Postnatal

Exposure to Low Levels of Arsenic in Public Drinking Water Linked to Lower Birthweight, Preterm Birth, Study Finds

Posted on by Jodi Snare

Babies born to mothers potentially exposed to low levels of arsenic in public drinking water—even at levels below the federal safety standard—were more likely to be born preterm, with lower birthweight, or be smaller than expected, according to a study funded by the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) Program.

While the U.S. Environmental Protection Agency sets a maximum contaminant level of 10 micrograms per liter for arsenic in public water systems, this study examines how even lower-level arsenic exposures may still affect pregnancy outcomes in a large population. Previous research largely focused on private wells or smaller study groups.

Because arsenic occurs naturally, water that comes in contact with certain rocks and soils may contain it. Contamination from various industrial processes also contributes to increased levels of arsenic in some areas.

“Most U.S. residents rely on public drinking water, and our findings suggest that further reducing arsenic in public water systems could be an important step to improve infant health across the U.S.,” said Anne Nigra, PhD, of Columbia University’s Mailman School of Public Health. “Even low levels of arsenic in public drinking water were associated with low birthweight and other adverse birth outcomes in U.S. infants.”

Key takeaways include:

  • Potential arsenic exposure during pregnancy—even at levels below the current federal safety standard—may be linked to adverse birth outcomes.
  • Mothers exposed to higher levels of arsenic in public drinking water were more likely to have babies born with low birthweight or smaller than expected for the number of weeks of pregnancy.
  • These patterns were seen across several racial and ethnic groups, including White, Black, and Hispanic/Latino families. Similar risks were also observed among babies born to American Indian, Alaskan Native, Native Hawaiian, and Pacific Islander parents.
  • Babies born to Black parents faced higher risks of being born early, having low birthweight, or being smaller than expected.

Researchers analyzed data from nearly 14,000 mother-infant pairs from the ECHO Cohort. Arsenic exposures during pregnancy were estimated by combining water quality data with the residential histories of participants. No actual arsenic levels were tested for these participants.

This collaborative research was published in JAMA Network Open.

Nigra, A., et al. (2025) Public water arsenic and birth outcomes in the Environmental influences on Child Health Outcomes Cohort. JAMA Network Open. DOI: 10.1001/jamanetworkopen.2025.14084

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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.

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A Diet High in Refined Grains and Low in Whole Grains in Pregnancy Linked to Lower Birthweights and Pre-term Births

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A Diet High in Refined Grains and Low in Whole Grains in Pregnancy Linked to Lower Birthweights and Pre-term Births

Analyzing Diets Based on Racial and Ethnic Groups May Better Predict Outcomes

Authors: Luis E. Maldonado, 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?

Researchers wanted to understand how a pregnant person’s diet, especially in relation to their blood sugar levels (fasting blood glucose), affects birth outcomes—like the baby’s weight and whether the baby is born early. Higher fasting blood glucose during pregnancy is known to increase the risk of adverse birth outcomes. However, little is known about whether culturally influenced combinations of foods and beverages play a meaningful role across different racial and ethnic groups. This question is important because, in the U.S., Hispanic pregnant women are disproportionately affected by adverse birth outcomes, such as preterm birth and low birthweight (under 5.5 pounds). By examining dietary patterns within racial and ethnic groups, the researchers aimed to uncover more precise links between diet and birth outcomes. These links might be overlooked when analyzing the population as a whole, since average diets often reflect the eating patterns of the most represented groups in the study.

 

What were the study results?

Refined grains, such as white bread or white rice, showed the strongest association with higher fasting blood sugar levels among Hispanic and non-Hispanic White women. People who ate diets high in refined grains and low in whole grains were more likely to have babies born with low birthweight, smaller for gestational age, or born preterm.

When dietary patterns were analyzed by racial and ethnic group, the associations between diet, blood sugar, and birth outcomes were stronger than when using a single pattern for the full population. In the group that included non-Hispanic White and Hispanic participants, nuts, seeds, and solid fats such as butter and lard were linked to lower blood sugar. Among non-Hispanic White participants, whole grains and solid fats had the strongest association with improved blood sugar control. In contrast, among Hispanic participants, higher fruit consumption was associated with elevated blood sugar levels. These food-specific associations should be considered within the overall dietary pattern, as individual foods can influence blood sugar – beneficially or adversely – within the broader diet.

 

What was the study's impact?

The results of this study show the importance of looking at dietary patterns within racial and ethnic groups, particularly in studies with varying representation of different racial and ethnic populations. Analyzing a single, combined group may mask group-specific associations between diet and birth outcomes, as the effects of diet can differ across racial and ethnic backgrounds.

 

Who was involved?

The study included 420 Hispanic and 564 non-Hispanic White pregnant participants from two ECHO Cohort study sites.

 

What happened during the study?

During the study, participants shared details about what they ate over a 24-hour period. The researchers analyzed the diets, along with the mother’s blood sugar, to help determine which combinations of foods eaten together in an overall diet are most closely linked to changes in blood sugar levels. They then tested whether the links between diet and birth outcomes were different across racial and ethnic groups by comparing findings from diets derived using group-specific versus combined fasting blood glucose, which have also been previously shown to vary by racial and ethnic population.

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 continue exploring how dietary patterns affect birth outcomes in diverse populations, especially by identifying patterns that are specific to different racial and ethnic groups.

 

Where can I learn more?

Access the full journal article, titled “Racial/Ethnic-Derived Maternal Diets Predict Birth Outcomes Better than a Diet Derived from a Combined Sample among Hispanic/Latina and non-Hispanic White Pregnant Individuals in the ECHO Cohort,” in Nutrition.

 

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

Published June 12, 2025

Read the related research article.

Download this summary

A Diet High in Refined Grains and Low in Whole Grains in Pregnancy Linked to Lower Birthweights and Pre-term Births

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Pregnancy and birth