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Wildfire smoke exposure increases risk of preterm birth, study finds

Posted at 4:31 PM, Sep 10, 2021

SAN DIEGO, Calif. — Wildfires across the West are sending toxic plumes of smoke into the air, affecting cities thousands of miles away.

And as fires grow more frequent and destructive, doctors are raising awareness about the possible risks for pregnant women and their unborn babies.

"Clinicians now are realizing that climate change is impacting our patients today because the events are happening so frequently," said Dr. Marya Zlatnik, OBGYN and maternal-fetal medicine expert at the University of California San Francisco.

Dr. Zlatnik says historically, medical education for pregnant women has focused more on individual choices impacting health, like smoking.

“There’s sort of this whole, broad category of risks we haven’t studied yet. But they’re things we have lots of reason to suspect shouldn’t be ingested by pregnant women or kids," said Dr. Zlatnik.

One year ago, the Bay Area woke to an apocalyptic, smoke-choked sky as fires burned throughout Northern California. Today, fires are consuming the state at the same pace.

The toxic particles in wildfire smoke are small enough to enter the lungs and bloodstream. And Dr. Zlatnik says researchers are now finding soot from wildfires in placentas.

“Anything that damages the placenta or causes inflammation in the placenta can potentially sort of directly harm the baby or lead to problems with pregnancy, like preterm birth, or the baby not growing as well.”

A study published last month found there may have been as many as 7,000 additional premature births in California attributable to wildfire smoke exposure between 2007 and 2012.

“That can have a lifelong impact for that baby. Prematurity is probably the number one cause of neural developmental problems and is certainly very expensive and very scary for parents," said Dr. Zlatnik. "Anything we can do to avoid unnecessary inflammation is something that could potentially really have long-term beneficial health impacts.”

Authors of the new study note that premature births cost the U.S. healthcare system an estimated $25 billion per year, and that even modest reductions in preterm birth risk could greatly benefit society.

Expecting her first child in October, Laura Canton says she's hyper-aware of the changing climate as she thinks about her daughter's future.

“When we walk on the beach, we see bottle caps, plastic bottles, Legos, just everywhere on the beach. It’s sad to know Ocean is going to grow up and may not get to go to Yosemite or the forest because it's going to be gone," said Canton.

Living in San Diego, she's experienced the hazy fog of wildfires.

“The clouds come in, and you can see it’s a different haze. The sunsets are really orange," said Canton. "It’s very dry here. So, if one house lights up, our houses are so close together, it could take down the whole city, it is scary.”

Dr. Zlatnik says there are steps pregnant women can take to protect themselves and their unborn children.

She recommends patients monitor air quality, checking the news, or using phone apps like AirVisual and Plume Air Report.

"The best way to improve air is to use either a home fan, air conditioning system that has a high-quality MERVE 13 filter that's going to filter out the PM2.5 material or a portable air cleaner, air purifier, that’s filtering out that particulate matter.”

A more affordable option, making one at home with a box fan and a furnace filter.

“I didn’t use to advise this for the women I care for in pregnancy, that they needed to invest in one of these things," said Dr. Zlatnik. "But that’s one of the ways that people who are pregnant can protect themselves.”