The study highlights the health risk of exposure to PM2.5 for pregnant women

For pregnant women, exposure to fine particulate air pollution (PM2.5) was associated with altered immune responses that may lead to adverse birth outcomes, according to a new study by Harvard School of Public Health TH Chan. The study is the first to examine the relationship between PM2.5 and maternal and fetal health at the single-cell level and highlights the health risk of PM2.5 exposure to pregnant women.

The study will be published Nov. 29 in Science Advances.

This study represents a substantial step forward in understanding the biological pathways through which PM2.5 exposure affects pregnancy, maternal health, and fetal development. His advanced methodology represents a major innovation in how we study immune responses to environmental exposures.”

Kari Nadeau, corresponding author, John Rock Professor of Climate and Population Studies and Chair of the Department of Environmental Health

Previous research has found associations between PM2.5 exposure and maternal and child health complications such as pre-eclampsia, low birth weight and developmental delays in early childhood. To understand these associations at the cellular level, the researchers used air quality data collected by the Environmental Protection Agency to calculate the study participants’ average exposure to PM2.5. Participants were both non-pregnant and 20 weeks pregnant. The researchers then used an innovative technology to understand how the pollution altered the DNA of the participants’ individual cells. Inside each cell they were able to map changes in histones, the proteins that help control the release of cytokines – proteins that help control inflammation in the body and that can affect pregnancy.

The study found that exposure to PM2.5 can affect the histone profiles of pregnant women, disrupting the normal balance of cytokine genes and leading to increased inflammation in both women and fetuses. In pregnant women, this increase in inflammation may correlate with adverse pregnancy outcomes.

“Our findings highlight the importance of minimizing air pollution exposure of pregnant women to protect maternal and fetal health,” said co-author Youn Soo Jung, research associate in the Department of Environmental Health. “Policy interventions to improve air quality, as well as clinical guidelines to help pregnant women reduce their exposure to pollution, could have a direct impact on reducing pregnancy complications.”

Other Harvard Chan authors included Abhinav Kaushik and Mary Johnson.

The study was funded by the National Institutes of Environmental Health Sciences (R01ES032253), the National Heart, Lung, and Blood Institute (R01HL081521), and the National Institute of Health/Environmental Protection (EPA R834596/NIEHS P01ES043HS/NIEHS P01ES043258 P20ES018173).