New study identifies link between air pollution and preterm birth

SALT LAKE CITY — A new study from the University of Utah published in the Journal of Exposure Science and Environmental Epidemiology found a link between preterm births and air pollution in Utah.

Brenna Kelly, the lead author of the study and an incoming responsible AI postdoctoral fellow at the university's Scientific Computing & Imaging Institute, along with other researchers, used machine learning to evaluate patterns in air pollution mixtures for birth records between 2013 and 2016 from 44,874 first-time mothers in Utah.

The study, published in May, found that "repeated exposure to combinations of common air pollutants in early pregnancy was associated with nearly three times greater odds of early preterm birth," according to a press release from the university.

Preterm birth is "delivery before 34 weeks' gestation, when infants face higher risks of health complications," per the release.

Utah's unique air

According to Kelly, the idea that air pollution has effects on preterm birth is "a fairly well-established hypothesis." What makes the study stand out is its focus on a combination of pollutants, not just individual ones.

At times, Utah has "some of the worst air quality in the world" due to inversions and wildfire smoke, she said. But the data showed most preterm births weren't related to either of those things.

Preterm births in the state were highly linked to "a really common co-exposure between ozone (O3) and fine particulate matter (PM2.5)," and at a fairly low level, Kelly told Deseret News. The level of those mixtures in the atmosphere associated with preterm births "would be considered a healthy day" by tools like a weather app.

What pregnant women should know

"Exposure to a mixture of O3 and PM2.5 in the late first trimester had the strongest relationship to early preterm birth," according to the press release.

There are signs people can look for that indicate levels of those pollutants in the air. Kelly said PM2.5 can often be seen, and while O3 is invisible, it peaks "in the late afternoon after the hottest portion of the day."

"It would be ideal if we didn't put so much pollution into the environment, but the fact is that these exposures exist," Kelly said.

Spreading awareness of the effects exposure to those mixtures can have on pregnancy can help pregnant women make smart changes. "Maybe your evening walk should become a morning walk to limit your exposure," she said.

Kelly also noted that getting outside and being active are healthy practices, and "it's a shame" to ask pregnant women to modify their behaviors "because we expect so much of pregnant people already."

Kelly said more research and better resources are needed, but just knowing the air quality index on weather forecasts is limited and making small behavioral changes are a start to preventing preterm birth.

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