Study Reveals How Even Small Amounts of Arsenic in Water Are Risky for Pregnancy

A new study published in JAMA Network Open reveals that even low levels of arsenic in public drinking water-below the current federal safety standard-may be linked to adverse birth outcomes, including preterm birth and low birthweight. The study funded by the National Institutes of Health’s Environmental Influences on Child Health Outcomes (ECHO) Program.

Arsenic, a naturally occurring element, can seep into water supplies through contact with certain rocks and soils, as well as through contamination from industrial processes.

Researchers analyzed data from nearly 14,000 mother-infant pairs participating in the ECHO Cohort. They estimated arsenic exposure by combining nationwide water quality data with participants’ residential histories during pregnancy. No direct testing of arsenic levels in the participants' bodies was conducted. The study found that higher arsenic exposure was associated with a greater risk of babies being born smaller than expected for their gestational age or at low birthweight. These associations were consistent across various racial and ethnic groups.

Importantly, babies born to Black parents were found to face higher risks of being born early, underweight, or smaller than expected-highlighting how environmental exposure may compound existing health disparities.

The findings emphasize the need to re-evaluate federal drinking water standards and call for additional public health measures to reduce arsenic exposure, even at currently “safe” levels.

Reference: Nigra AE, Bloomquist TR, Rajeev T, et al. Public Water Arsenic and Birth Outcomes in the Environmental Influences on Child Health Outcomes Cohort. JAMA Netw Open. 2025;8(6):e2514084. doi:10.1001/jamanetworkopen.2025.14084