Exposure to low levels of arsenic in public drinking water linked to lower birthweight, preterm birth, study finds

(Press-News.org) 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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