Exposure to wildfire smoke during pregnancy increases the risk of preterm birth-ScienceDaily

The study was published on August 14th Environmental researchIt turns out that there could have been as many as 7,000 premature births in California due to exposure to wildfire smoke between 2007 and 2012. These births occur 37 weeks before pregnancy, and imperfect development increases the risk of various neurodevelopmental, gastrointestinal, respiratory complications, and even death. ..

Wildfire smoke contains high levels of the smallest and most deadly type of particle contamination known as PM2.5. The spots on these toxic soot and particulate matter are so fine that they can be embedded deep in the lungs and into the bloodstream, similar to the oxygen molecules needed to survive.

The study takes place as a large wildfire reignites the dry landscape of the western United States-a historic wildfire season has burned more than 4 million acres of California and has been recorded in the state to date. Only a year after producing some of the worst daily air pollution. During the 2020 fire season, more than half of the state’s population experienced a month of wildfire smoke levels ranging from unhealthy to dangerous.

Marshall Burke, an environmental economist at Stanford University, who co-authored the new study, said it could get worse this year. Nonetheless, there are many uncertainties about the health effects of these harmful plumes. These plumes contribute to the increased portion of particulate pollution across the country and have a different chemical composition than other surrounding sources of PM2.5, such as agriculture, tailpipe emissions and industry.

One possible explanation for the link between wildfire smoke exposure and preterm birth is that pollution causes an inflammatory response that can initiate labor. The increased risk is relatively small in relation to all the factors that contribute to the birth of a healthy full-term baby. “But finding clues like this against a background where we know very little about why some women give birth too early, prematurely, and others don’t. Helps to stitch together larger puzzles, “said co-author Gary Shaw. DrPH, a professor of pediatrics and co-principal researcher at the March of Dimes Premature Infant Research Center at Stanford University.

Extreme wildfire

New results show that wildfire smoke accounts for more than 6% of preterm births in California during the worst smoke years of the 2008 survey period, when heavy thunderstorms, strong winds, high temperatures and dry landscapes had fatal consequences. Indicates that it may have contributed. And the Destructive Fire Season-A season now dwarfed by the record Inferno of 2020 and the fiery ongoing flames of Dixie in Northern California.

“In the future, the confluence of factors such as climate change, centuries of fire control, and the construction of homes around fire-prone forests will result in frequent and intense exposure to wildfire smoke throughout the west. As a result, exposure to smoke, including premature births, is likely to increase the health burden. “

This study provides new evidence of the value of investing in open burning, mechanical thinning, or other efforts to reduce the risk of extreme wildfires. Given that preterm birth costs an estimated $ 25 billion annually in the U.S. healthcare system, even a slight reduction in preterm birth risk can bring “huge social benefits,” said Stanford’s Faculty of Global Energy and Environment. Burke, an associate professor of earth systems science, said. Science (Stanford Earth). “Our research emphasizes that reducing the risk of wildfires and the associated air pollution is one way to achieve these social benefits.”

“There is no safe level of exposure”

Researchers analyzed satellite data from the National Oceanic and Atmospheric Administration (NOAA) for smoke plumes to identify smoke days for each of the 2,610 zip codes. They developed these data using machine learning algorithms that incorporate data from air quality sensors, satellite observations, and computer models of how chemicals move through the Earth’s atmosphere. Combined with estimates of PM2.5 contamination at the ground level. They pulled additional data from California’s birth record. However, twins, triplets, and multiples above that usually arrive early.

Preterm birth patterns within each zip code, after considering other factors known to affect the risk of preterm birth, such as temperature, baseline contamination exposure, maternal age, income, race, ethnic background, etc. However, the number of days of smoke in that place was higher than usual.

They found that each day of increased exposure to smoke during pregnancy increased the risk of preterm birth, regardless of race, ethnicity, or income. Also, a week’s exposure corresponds to a 3.4% higher risk than mothers who have not been exposed to wildfire smoke. Intense smoke exposure during late pregnancy (between 14 and 26 weeks gestation) had the strongest effect, especially when smoke added more than 5 micrograms per cubic meter to the daily PM 2.5 concentration. “If you can avoid exposure to smoke by staying indoors or wearing the right mask outdoors, it will be a good health habit for everyone,” Shaw said.

The findings are based on established associations between particle contamination and adverse birth outcomes, such as preterm birth, low birth weight, and infant mortality. However, this study was one of the first to isolate the prenatal effects of wildfire smoke and to clarify the importance of timing of exposure.

“Our study, along with many other recent papers, clearly shows that there are no safe levels of exposure to particulate matter. Exposures above zero can exacerbate health effects. “There is,” said Burke, who is also the Deputy Director of the Food Security Center. Environmental and Senior Research Fellow, Freeman Spogli International Institute, Stanford University. “As a society, it is very difficult to completely eliminate all pollutants from the atmosphere, but our research shows that it is possible to reduce major pollutants further than the current” acceptable “levels in public health. Suggests that it can be very beneficial to. “

This work was supported by the Robert Wood Johnson Foundation and the March of Dime Preterm Research Center at Stanford University School of Medicine.