Utah’s air pollution cocktail linked to preterm birth, study says

The air pollution cocktail that expectant mothers often breathe in Utah is associated with more preterm births, University of Utah researchers found in a new study. 

That repeated exposure to a combination of air pollutants during early pregnancy stages, even in moderate levels, is associated with nearly three times greater odds of preterm birth, researchers found. That’s when infants face higher risks of health complications. 

“People are exposed to multiple things at once, over multiple times,” Brenna Kelly, lead author of the study said in a news release. 

The findings “raise questions about whether current air quality index (AQI) ratings — typically based on the single pollutant posing the greatest harm — may be missing serious health risks to the public,” according to the release.

Pregnancy puts higher oxygen demands on expectant mothers, so when air quality is unhealthy, they also breathe in a larger quantity of pollutants, the release said. Previous studies had linked individual air pollutants, like PM2.5 or ozone, to delivery before 34 weeks of gestation. But, according to University of Utah researchers, those studies haven’t taken a deep dive into the exposure of multiple pollutants at the same time. 

For this new study published in June, researchers used artificial intelligence to study a cohort of almost 45,000 first-time expectant mothers who gave birth in Utah, which has occasionally experienced some of the worst short-term air quality in the country. At the time of the study, Utah also had several non-attainment areas, where air pollution levels consistently exceed healthy standards. 

Because the air quality index doesn’t take the exposure to multiple pollutants into account for its ratings, the Environmental Protection Agency considers the contamination levels of individual pollutants to be safe. However, when mixed, they may still represent health risks, according to researchers. Exposure to a mixture of ozone and fine particulate matter in the late first trimester of pregnancy, for example, had the strongest link to preterm birth.

“Early pregnancy is a critical period because the placenta and arteries that supply blood and oxygen to the fetus are still developing,” Michelle Debbink, associate professor of obstetrics and gynecology at the university and coauthor of the study, said in a prepared statement.

“Exposure to pollutants at this juncture could impair this process, increasing the risk of complications such as preeclampsia, which can require preterm delivery,” Debbink said. “Repeated exposures could also cause inflammation and damage that accumulates over time, further increasing the risk of preterm birth.”