Boston, MA – Researchers at Harvard T.H. Chan School of Public Health have just published a new study that demonstrates how fine particulate air pollution PM2.5 disrupts the immune responses of pregnant women and may cause adverse birth outcomes. Published on 29 November 2024 in Science Advances, this study is the first attempt to determine whether exposure to PM2.5 changes health at the single-cell level for both the mother and her fetus.
“This study is a huge leap forward in understanding how exposure to PM2.5 influences biological pathways leading to effects on pregnancy, maternal health and fetal development,” says lead author Kari Nadeau, also the John Rock Professor of Climate and Population Studies. “The authors employed novel approaches in the field to assess how environmental exposures elicit immune responses.”.
The findings underscore the urgent need to address air pollution’s impact on vulnerable populations, especially pregnant women, and offer actionable insights for policymakers and healthcare providers.
This study, which was published in Science Advances on 29 November 2024, is the first one focused on finding whether exposure to PM2.5 can affect the health of a mother and her fetus at the single-cell level.
Lead author and John Rock Professor of Climate and Population Studies Kari Nadeau says, “This study is a tremendous leap forward in understanding the impact that exposure to PM2.5 influences along pathways down on biologies leading into effects on pregnancy, maternal health, and fetal development.”.
There had been previous studies that related PM2.5 exposure with preeclampsia, low birth weight, and developmental delay of the child. This study extends further by explaining how PM2.5 exposure impacts maternal and fetal health at the cell level, hence new information on mechanisms on outcomes.
To understand the biological effects of PM2.5, researchers used Environmental Protection Agency (EPA) air quality data to measure participants’ average exposure. The study included both nonpregnant women and women who were 20 weeks pregnant. Advanced single-cell technology was used to determine how the histones, proteins that can regulate gene expression, and cytokines, proteins that are critical in the immune system inflammatory responses, were affected by the presence of PM2.5.
The analysis depicted that PM2.5 exposure altered the histone profiles of pregnant women as it disrupted cytokine gene activity and increased inflammation. A range of complications in pregnancies, such as restricted growth of the fetus, are associated with chronic inflammation, preterm labor, etc.
Our findings underscore the need to minimize air pollution exposure in pregnant women for maternal and fetal health,” said Youn Soo Jung, co-author and research associate in the Department of Environmental Health. The research implies that such an immune system interference could be critical for both mothers and their fetuses.
Implications on Maternal and Fetal Health
Inflammation generally tends to play a key role in the human body’s immune function. Excessive and chronic inflammation during pregnancy can contribute to harmful effects. This study highlights how air pollution disrupts critical cellular functions, which may contribute to poor birth outcomes.
The elevated maternal inflammation can affect normal development of fetuses and therefore may pose long-term health challenges. This, again, highlights the importance of increased awareness about the potential risks that are posed by PM2.5 exposure, particularly in urban regions where the pollution levels are generally higher.
Policy and Clinical Recommendations
More comprehensive policy interventions would be needed to mitigate the risks of PM2.5. Strict emission-control regulations on industry, incentives for transportation technologies that are cleaner, and targeted public health campaigns to make people more aware of the dangers associated with air pollution would be necessary.
The study provides practical steps a pregnant woman can take individually to reduce exposure. The recommendations include not engaging in outdoor activities when there is high air pollution, indoor air purifiers, and protection through masks when within the polluted areas.
Policy interventions on air quality, and clinical guidelines on how pregnant women can minimize exposure to pollution, could immediately impact reducing pregnancy complications, Jung said. Such interventions would reduce healthcare expenses while improving health outcomes for mothers and their children.
Research Support and Collaboration
Titled “Impact of air pollution exposure on cytokines and histone modification profiles at single-cell levels during pregnancy,” the study brought together researchers from several institutes and represented a collaborative effort. From Stanford University and the University of California, Berkeley, the paper brings contributions from Harvard researchers Abhinav Kaushik and Mary Johnson among them.
The study was funded by the National Institutes of Environmental Health Sciences, the National Heart, Lung, and Blood Institute, and the National Institutes of Health/Environmental Protection Agency. This funding demonstrates that air pollution is a significant issue in public health.
Broader Implications and Future Research
Although this study is focusing on the PM2.5 effect in pregnancy, its findings might be used toward understanding the contribution of air pollution to diseases other than pregnancy. With the advanced methodology applied here, further research regarding how environmental exposure influences both immune function and chronic diseases would be developed.
Future studies may explore long-term health effects for children who have been exposed in utero to PM2.5 and examine other environmental exposures, such as chemical pollutants or heatwaves, as modifiers of the air pollution-health impact relationship.
A Call to Action
The continuing trend of increasing urbanization and industrialization indicates that air pollution is still a global health risk. The study is a call to be reminded of environmental dangers in hiding, especially with respect to vulnerable populations such as pregnant women and their unborn children.
Air quality can improve by reducing exposure as a means of protecting maternal and fetal health through knowledge and tools acquired.
Dr. Nadeau continues, “This study marks a milestone in understanding and dealing with the challenges presented by air pollution. It puts it bluntly to policy-makers, health professionals, and the international community on the need for urgent priority towards clean air for future generations.”.
Addressing air pollution today is not only a measure for public health but also an important step toward making sure mothers, children, and society at large achieve better health outcomes.