Pregnant woman on sofa holding stuffed toy.

Wildfire smoke and heat exposure before pregnancy linked to lower birth weights

Pregnant people exposed to wildfire smoke and extreme heat in the weeks before or during early pregnancy may face a higher risk of delivering smaller-than-expected babies, according to a new study.

Sharon Udasin reports for The Hill.

In short:

A study of 713 births in Los Angeles between 2016 and 2020 found that exposure to wildfire smoke and heat stress just before or early in pregnancy correlated with babies born small for their gestational age.
The researchers used wildfire data from CalFIRE and smoke density data from the National Oceanic and Atmospheric Administration to estimate individual exposure levels, combining this with neighborhood-level climate vulnerability indexes.
Heat exposure before pregnancy, especially in socioeconomically vulnerable areas, was also linked to higher odds of adverse birth outcomes, emphasizing the role of where someone lives and when they are exposed.

Key quote:

“Where you live makes a difference in your health. So does the timing of your exposure during or immediately before pregnancy.”

— Roxana Khalili, postdoctoral researcher at the University of Southern California

Why this matters:

The intersection of wildfire smoke, extreme heat, and pregnancy raises urgent public health concerns as climate change drives more intense fire seasons and heatwaves. Fine particle pollution from wildfire smoke can enter the bloodstream and affect fetal development, while heat stress may strain the body’s ability to regulate temperature during pregnancy. Both are more likely to impact people living in low-income neighborhoods where access to air conditioning, clean air, and prenatal care is limited. These findings point to long-term health risks for children born into communities already burdened by environmental injustice and limited infrastructure. As wildfire smoke and extreme heat become more common, understanding these risks becomes vital for shaping public health responses.

thehill.com

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