Up to 7,000 pre-term births in California over a six-year period may be linked to wildfire smoke exposure during an expecting mothers' pregnancies, a new study finds.
Stanford University researchers analyzed data on three million births in California between 2006 and 2012, finding that expecting mothers who were exposed to wildfire smoke were more likely to give birth early - putting their babies at risk of developmental conditions.
Even when the researchers adjusted their analysis for other demographic factors, they still found a connection between smoke exposure and pre-term birth.
With every additional week of smoke exposure, an expecting mother had a 3.4 percent higher risk of pre-term birth - compared to a mother who wasn't exposed to smoke.
The study demonstrates the dangers of wildfire smoke, indicating that expecting mothers should be especially careful to stay indoors or wear a mask when smoke risk is present.
Exposure from wildfire smoke may increase an expecting mother's risk of giving birth early, a new study finds. Pictured: Firefighters battle a fire in Diamond Bar, California, during the 2008 fire season. The fire led to particularly high pre-term birth numbers
Overall, about 3.7 percent of pre-term births between 2007 and 2012 could be linked to wildfire smoke, the researchers estimated. Impact varied by year and ZIP code
There are 23 wildfires currently burning across California, as of September 7.
One of those fires - in Dixie - has been burning since mid-July, impacting almost one million acres across the state.
The state is seeing a second devastating fire season, after over four million acres burned and smoke painted the sky orange in 2020.
Wildfire smoke contains high levels of PM2.5 particle pollution, a highly dangerous form of pollution generated from burning wood and fossil fuels.
PM2.5 pollution can damage the lungs, enter the bloodstream, and impact people's health in numerous ways - ranging from asthma to Alzheimer's.
A new study suggests that this wildfire smoke can be particularly dangerous to babies, as mothers exposed to smoke during their pregnancies may be more likely to give birth early.
This study from Stanford researchers - published in the journal Environmental Research in August - builds upon past research suggesting links between smoke exposure and worse birth outcomes.
In a pre-term birth, a baby is born before 37 weeks of pregnancy have been completed.
Pre-term babies have incomplete development - leading to increased risk of neurodevelopmental, gastrointestinal, and respiratory complications.
The Stanford researchers hypothesize that pollution exposure could 'trigger an inflammatory response' which causes a mother to deliver early.
The Stanford researchers analyzed data on every singleton birth (meaning no births of twins) in California between 2006 and 2012. This included about three million births in total.
The researchers linked birth data with satellite data on smoke and
