Containing a high amount of fine particles, the smoke from forest fires can cause childbirth before the 37th week of pregnancy in pregnant women who breathe it.
- Exposure to fine particles released by forest fires can trigger an inflammatory reaction, itself responsible for premature birth.
- Exposure to high levels of fine particles for a week increases the risk of preterm delivery by 3.4%.
From Greece to Var, via Algeria, Turkey and even Bolivia, devastating fires have been observed in recent weeks, ravaging the fauna and flora and spreading toxic fumes over kilometers. These fumes persist for a long time in the atmosphere. They can not only damage the heart and lungs and trigger allergic and inflammatory respiratory diseases, but also increase the risk of premature delivery.
This is highlighted by a new study conducted by Stanford University (United States) and published in the journal Environmental Research. According to its authors, up to 7,000 additional premature births in California are attributable to exposure to smoke from wildfires between 2007 and 2012. These births occurred before 37 weeks of pregnancy, which increases the risk of complications neurodevelopmental, gastrointestinal and respiratory damage, and even death.
A high level of fine particles in the air
Previous studies have established that wildfire smoke contains high levels of fine particles with a diameter of 2.5 micrometers or less. Called PM2.5, these airborne particles are about 3% the diameter of a human hair and can penetrate deep into the airways, enter the bloodstream and damage vital organs.
According to the authors, one possible explanation for the link between wildfire smoke exposure and premature births is that the pollution can trigger an inflammatory response that then triggers labor. To test this hypothesis, they first analyzed satellite smoke plume data from the National Oceanic and Atmospheric Administration (NOAA) to identify smoke days recorded in California in 2020. They then combined this data with estimates of the ground-level pollution by PM 2.5, developed using an algorithm. Finally, they extracted data from California birth records.
A 3.4% increased risk for one week of smoke exposure
Even taking into account other risk factors for preterm birth, the researchers found that each additional day of smoke exposure during pregnancy increased the risk of preterm birth. Thus, a full week of exposure translates to a 3.4% increased risk compared to a mother not exposed to wildfire smoke.
This risk of premature birth is even greater if exposure to smoke occurs during the 2and trimester of pregnancy.
“Our work, along with a number of other recent papers, makes it clear that there is no safe level of exposure to particles. Any exposure above zero can worsen health effects, says Marshall Burke, environmental economist at Stanford and co-author of the study. Although it will be extremely difficult as a society to completely eliminate all pollutants from the air, our research suggests that further reductions in key pollutants below current “acceptable” levels could be massively beneficial to public health. .”
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