Story at a glance
- Findings are based on data from 161 pairs of mothers and infants.
- Higher levels of prenatal exposure were linked with lower cognitive outcome scores among children.
- However, the timing of exposure also played a key role.
Children born to mothers exposed to higher levels of ambient air pollution during mid- to late-pregnancy tend to show deficits in motor coordination, cognition and language skills at the age of two, a new study found.
Researchers assessed 161 pairs of Latino mothers and children. After participants provided detailed accounts of where they lived, researchers used data from the U.S. Environmental Protection Agency’s Air Quality System to determine exposure to roadside traffic, industry and wildfire smoke pollutants.
They measured prenatal exposure to nitrogen dioxide and particulate matter smaller than 2.5 and 10 microns in diameter (PM2.5 and PM10, respectively) during the first, middle and last three months of pregnancy. Children completed a series of neurodevelopmental tests at age two.
“Our findings suggest that pollution exposure, particularly during mid- to late-pregnancy, may negatively impact neurodevelopment in early life,” senior author Tanya Alderete said in a release. Alderete is an assistant professor of integrative physiology at University of Colorado Boulder.
Data showed infants prenatally exposed to PM10 levels at the 75th percentile scored three points lower on cognitive tests compared with infants exposed at the 25th percentile.
Findings were consistent even after adjusting for socioeconomic status, number of breastfeeding times per day and time of delivery, along with other factors.
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Timing of exposure played an important role in children’s developmental outcomes. During mid- to late- pregnancy, key circuits in the brain that support sensory, motor and communication systems form, explained author Zach Morgan.
“The brain develops differently at different stages of pregnancy and when you have a disruption at a critical window that can affect the trajectory of that development,” Morgan said.
Although more studies are needed to understand how the pollutants affect developing brains, researchers note inhaled pollutants may come in contact with the fetus, potentially causing inflammation and oxidative stress that could alter neurodevelopment. Exposure might also affect babies’ gut microbiomes in ways that promote inflammation, potentially impacting brain health.
According to the World Health Organization, more than 90 percent of the global population is exposed to unhealthy levels of particulate matter. But in the United States, racial and ethnic minorities and low-income populations bear a disproportionate burden of exposure.
Previous research has shown Black Americans experience 56 percent more exposure to air pollution than they are responsible for creating. For Latinos, that total rises to 63 percent.
“Our findings highlight the importance of addressing the impact of pollution on disadvantaged communities and point to additional steps all families can take to protect their health,” said Alderete. She added that pregnant women should be vigilant about avoiding air pollutants when possible, especially in the later stages of pregnancy.
These women could invest in in-home air filtration systems, avoid exercising outdoors on high pollution days and avoid second-hand smoke.
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