Molecular Link Between Air Pollution and Pregnancy Risks

A new study by researchers at Emory University, published in Environmental Science & Technology, has found that exposure to tiny particles in the air during pregnancy can disrupt the mother’s metabolism and alter important biological processes. These changes were associated with an increased risk of various adverse birth outcomes, including preterm birth. The study, which analyzed blood samples from 330 pregnant women in the Atlanta metropolitan area, is believed to be the first to examine how exposure to fine particulate matter (PM2.5), commonly found in air pollution, affects the metabolism of pregnant women and contributes to an increased risk of preterm and low birth weight.

What Role do Fine Dust Particles Play in Pregnancy Risks?

“The link between air pollution and preterm birth has been known for a long time, but for the first time, we were able to examine the exact pathway and specific particulate matter to determine how it affects the increased risk of adverse birth outcomes,” said Donghai Liang, PhD, lead author of the study and associate professor of environmental health at the Rollins School of Public Health. “This is important because understanding the ‘why’ and ‘how’ will help us better know how to address it.”

Previous research has shown that pregnant women and fetuses are more vulnerable to PM2.5—which comes from combustion sources such as vehicle exhaust, industrial processes, and wildfires—than other population groups, including an increased likelihood of preterm birth (before 37 weeks of gestation), which is the leading cause of death among children under five worldwide. Premature births are also associated with complications such as cerebral palsy, respiratory distress syndrome, and long-term risks for noncommunicable diseases, while preterm births (37–39 weeks of gestation) are also associated with increased neonatal mortality and developmental problems. Approximately 10% of premature births worldwide are attributable to exposure to PM2.5.

Key Findings

• This was the first study to uncover the specific pathways and molecules in energy and amino acid metabolism that may explain how exposure to PM2.5 contributes to preterm birth and preterm birth.
• The researchers identified two substances—cortexolone and LysoPE(20:3)—as factors linking short-term air pollution to an increased risk of preterm birth, providing a possible mechanism by which air pollution triggers premature labor.
• The study highlighted protein digestion and absorption disorders—which are critical for fetal development and immune function—as possible links between air pollution and preterm birth, providing new potential targets for preventive measures.
• Of the 330 women who participated in the Emory study, 66 (20%) gave birth to preterm infants and 54 (16.4%) gave birth to premature infants, both of which are significantly higher than the prevalence in the general US population.

Reducing Harmful Effects

“As a scientist studying air pollution, I don’t believe that air pollution will disappear anytime soon. Even at lower levels, we continue to see adverse health effects, but we can’t just tell people to move away from highly polluted areas,” says Liang. From a clinical perspective, it is therefore crucial to gain a better understanding of these pathways and molecules affected by pollution. In the future, researchers may then be able to target some of these molecules to develop effective strategies or clinical interventions that could help reduce these harmful health effects.