The University of Maryland School of Public Health announced on September 15, 2026 a $2.5 million grant from the National Institutes of Health to fund what’s described as the largest study to date on how extreme heat, wildfire smoke, and other pollutants jointly affect maternal health in the United States.
Principal investigator Dr. Jennifer Stowell, an environmental epidemiologist and assistant professor in SPH’s Department of Global, Environmental and Occupational Health, said: “We aim to identify which pollutant combinations and what time periods during pregnancy matter most and to map out how risk looks across different areas. What we learn from this research will provide crucial information for clinical guidance, improved services in under-resourced perinatal care regions, such as rural areas, and better early-warning systems for high-risk groups like low income and minority populations.”
A Combined-Exposure Study, at Scale
Drawing on data from 6.5 million births over two decades, Stowell and her colleagues will measure exposure to extreme heat, wildfire smoke particles (PM2.5), and other pollutants against the incidence of serious pregnancy complications, including hypertension and gestational diabetes. Hypertensive disorders of pregnancy affect an estimated 10% of U.S. pregnancies, and gestational diabetes mellitus affects roughly 8% — both disproportionately impacting marginalized communities. Pregnancy reduces the body’s ability to regulate heat and places added demand on the heart and respiratory system, making pregnant people especially vulnerable to both hazards. Wildfire smoke particles and elevated heat days have each separately been linked to smaller average fetal size, preterm birth, and low birthweight, and extreme heat and regular air pollution are separately linked to pregnancy complications and loss, cardiovascular stress, and postpartum mental health effects — but little is currently known about wildfire smoke’s impact on pregnancy specifically.
Why Studying Them Together Matters
“We will look at the effect of exposure to all of these things at once, because they are increasingly happening all at once. And combined exposure could mean greater damage to the heart and respiratory system, which uniquely affects pregnant people and their babies,” Stowell said. “We hope this study will help us better understand these effects, so we can better protect millions of women exposed to wildfire smoke and heat each year.”
The $2.5 million grant is funded under NIH grant number 1R01HD119447-01A1. The content of the research is solely the responsibility of the study’s authors and does not necessarily represent the official views of the National Institutes of Health.
About the University of Maryland School of Public Health
The University of Maryland School of Public Health was established in 2007 and offers more than 30 academic programs across six academic departments, including epidemiology and biostatistics and global, environmental, and occupational health. The school is accredited by the Council on Education for Public Health and is currently ranked No. 22 among public health schools nationally by U.S. News & World Report.
About the National Institutes of Health (NIH)
The National Institutes of Health, part of the U.S. Department of Health and Human Services, is the nation’s primary agency for biomedical and public health research and the world’s largest public funder of biomedical research, supporting studies at universities, hospitals, and medical centers across the country.
