"Researchers have long warned that tiny air pollutants — 30 times smaller than the width of a human hair — are linked to preterm births. 

Now they’re one step closer to knowing why: Breathing in these tiny particles — largely caused by traffic, industry, burning fossil fuels and wildfire smoke — disrupts the molecules in pregnant women’s blood, raising the risk for preterm and early births, according to a new study from Emory University. 

The study, published in Environmental Science & Technology, is the first to examine what the pollutants are doing to a pregnant woman’s body that could trigger early labor. The research comes as the Trump administration signals that it wants to roll back standards governing the release of particulate matter known as PM2.5, defined as fine inhalable particles with diameters that are generally 2.5 micrometers and smaller.  

PM2.5 is behind an estimated 10% of all global preterm births, defined as babies born before 37 weeks of pregnancy, and preterm births account for 17% of deaths for children under 5 years old around the globe."

Brian Bienkowski reports for The New Lede June 4 2025. [2]