Preterm birth rates in California declined after nearby oil and coal power plants
shut down, researchers found.
These plants emit a variety of air pollutants and increasingly are shuttering as the
country turns to alternative sources of power.
Researchers set out to look at the impact of the plants on preterm births by analyzing
records on just over 57,000 births in California from 2001-’11. Of those, 6.5% were
preterm, defined as less than 37 weeks’ gestation. The team also studied Energy Information
Administration data on eight nearby power plants. The plants emitted about 177 tons
of nitrogen oxides each year before closing and 4 tons afterwards.
The study found that after plant closures, preterm births fell from 7% to 5% for families
living within 5 kilometers (km). There were smaller declines for those living 5-10
km from the plants. The decreases were greater for black and Asian babies than for
white and Hispanic.
“Air pollution may increase risk of preterm birth by altering normally progressing
gestation through activation of pro-inflammatory cytokines, preeclampsia, growth restriction,
or increased maternal susceptibility to infection,” authors wrote.
The findings are adjusted for a mother’s race, economic status, education and age.
Researchers used mothers living 10-20 km from a plant as a comparison group. They
also performed the analysis on mothers living near plants that did not close and found
preterm birth rates did not change.
In a news release, they pointed to another study that found fertility improved after
coal and oil power plant closures and said the research could impact states’ energy
“We believe that these papers have important implications for understanding the potential
short-term community health benefits of climate and energy policy shifts and provide
some very good news on that front,” co-author Rachel Morello-Frosch, Ph.D., M.P.H.,
a University of California, Berkeley professor of environmental science, policy and
management, said in the release. “These studies indicate short-term beneficial impacts
on preterm birth rates overall and particularly for women of color.”