Smog During Pregnancy Threatens Newborn Health

TUESDAY, Feb. 18, 2025 (HealthDay News) -- Newborns are more likely to be born sickly if their moms are exposed to air pollution during pregnancy, a new study says.

A woman's exposure to air pollution during the last month of pregnancy can increase their newborn’s risk of landing in a neonatal intensive care unit (NICU), according to findings published recently in the journal Scientific Reports.

For example, the risk of a newborn requiring NICU treatment increased by 30% to 35% with their mom’s exposure to higher levels of nitrogen dioxide, a noxious gas produced by the burning of fossil fuels in cars and power plants, researchers found.

Likewise, a pregnant woman’s exposure to airborne fine particulate matter increased their baby’s risk of needing NICU treatment by 11% to 22%, researchers said. These particles are found in vehicle exhaust and smoke from wildfires.

“Our findings highlight the critical impact of air pollution during the final weeks of pregnancy, a time of heightened fetal vulnerability, and emphasize the significance of addressing air pollution exposure, even at lower levels,” lead researcher Yohane Phiri said in a news release. He's a postdoctoral research associate with the University at Buffalo’s Department of Epidemiology and Environmental Health.

For the study, researchers compared 2018 birth data against satellite data tracking air pollution levels across the United States.

Previous research already had linked air pollution to pregnancy complications like birth defects, preterm delivery and altered fetal growth, Phiri said.

The new study shows that these effects in the womb can be potentially life-threatening to a newborn, researchers said.

“We saw the strongest risks with nitrogen dioxide and intermediate risks with (fine particulates),” Phiri said.

The Midwest and Mid-Atlantic had the highest odds of NICU admission due to nitrogen dioxide exposure, researchers found.

The risk posed by fine particle matter varied with the seasons, but persisted along the West Coast and in the Southeast, researchers report. 

Summer brought the highest risk from fine particulates, but winter risks were highest in the Northeast.

The team also tested for ozone pollution and found no link between exposure and NICU treatment, except for during the summer.

“While our findings are not causal, limiting direct inference, they support local and national initiatives aimed at further reducing air pollution and improving air quality,” Phiri said. “Such efforts could ultimately benefit pregnant women by minimizing exposure to harmful pollutants and reducing associated neonatal health risks.”

More information

The National Institutes of Health has more about air pollution.

SOURCE: University at Buffalo, news release, Feb. 13, 2025