A recent study led by the University of Washington has established a significant link between wildfire smoke exposure and an increased likelihood of preterm birth among pregnant individuals. This research, published on November 3 in The Lancet Planetary Health, analyzed data from over 20,000 births in the contiguous United States from 2006 to 2020.
With approximately 10% of babies in the U.S. being born prematurely, understanding the factors contributing to this phenomenon is crucial. Preterm birth, defined as delivery before 37 weeks of gestation, is associated with various immediate and long-term health risks. The study”s lead author, Allison Sherris, a postdoctoral researcher in environmental and occupational health sciences, emphasized the importance of preventing preterm births for future health benefits.
The researchers focused on the impact of fine particulate matter, or PM2.5, originating from wildfire smoke. By estimating the average daily exposure of participants to wildfire PM2.5 and the number of days they experienced smoke exposure, the study found a clear correlation: stronger exposure to wildfire smoke was linked to higher rates of preterm birth.
Notably, the risk of preterm birth was heightened during mid-pregnancy, especially around the 21st week of gestation. In late pregnancy, the risk was closely tied to exposure to high concentrations of wildfire PM2.5, particularly levels exceeding 10 micrograms per cubic meter. Co-author Dr. Catherine Karr, a professor at the University of Washington, pointed out that the second trimester is critical for placental growth, suggesting that inhaled smoke particles could interfere with placental health.
The study observed that the link between wildfire smoke and preterm birth was most pronounced in the Western United States, where higher concentrations of wildfire PM2.5 were recorded. As exposure to additional micrograms per cubic meter of wildfire PM2.5 increased, so did the odds of preterm birth. This may be due to the more frequent wildfires in this region, which enhances the accuracy of the exposure model used in the study.
Researchers acknowledged that various factors, such as regional differences in smoke composition and external conditions like heat, could influence these results. Future investigations are necessary to explore the precise mechanisms by which wildfire smoke impacts preterm birth.
Given the compelling evidence linking wildfire smoke to adverse pregnancy outcomes, Sherris advocates for actionable steps. Public health initiatives could enhance messaging aimed at pregnant individuals, equipping them with strategies to protect themselves during wildfire events. Tailoring public health communications to highlight the vulnerabilities of pregnant individuals may help mitigate risks associated with wildfire smoke exposure.
Additional co-authors of the study included Logan Dearborn, Christine Loftus, Adam Szpiro, Joan Casey, Sindana Ilango, and Marissa Childs, all affiliated with the University of Washington. This research received funding from the Environmental influences on Child Health Outcomes (ECHO) program at the National Institutes of Health.
