The vast majority of the studies reviewed in the paper concluded that ozone and PM 2.5 are also associated with preterm births, low birth weights and stillbirths. One study found that high exposure to air pollution during the final trimester of pregnancy was linked to a 42 percent increase in the risk of stillbirth.
Another study, looking at almost half a million births in Florida in 2004 and 2005, found that for every 5 kilometers, or roughly 3 miles, closer a mother lives to a plant that uses garbage to produce energy, the risk of low birth weight increases by 3 percent. Living closer to power plants was also tied to a higher risk of preterm birth.
Mothers with asthma were at particularly high risk. One study found that severe preterm birth, defined as a birth that occurs fewer than 28 weeks into pregnancy, increased by 52 percent for asthmatic mothers exposed to high levels of air pollution.
Most of the studies that examined the link between air pollution and preterm birth or low birth weight found that the risks were greater for black mothers.
Catherine Garcia Flowers, a field organizer in Houston for Moms Clean Air Force, an advocacy group, said the paper was evidence that the federal government needed to tighten regulations against air pollution. “This is a moment of reckoning for racial injustice and health disparities,” Ms. Flowers said by email. “Doing nothing about air pollution, which so clearly has a greater impact on Black Americans, is racism in action.”
Premature birth and low birth weight can have consequences that last a lifetime, affecting such things as brain development and vulnerability to disease, according to Nathaniel DeNicola, another of the paper’s authors and an assistant professor of obstetrics and gynecology at George Washington University’s School of Medicine and Health Sciences.
“This really does set the stage for an entire generation,” Dr. DeNicola said.
That increased risk adds to the disproportionate burden faced by black women when it comes to pregnancy. Black mothers are 2.4 times more likely to have children with low birth weight than white women, a 2018 paper found. An analysis published last year found that the risk of stillbirth was as much as twice as great for black mothers as for whites across a number of wealthy countries.