Mothers who live in neighborhoods with plenty of grass, trees, or other green vegetation are more likely to deliver at full term and their babies are born at higher weights, compared to mothers who live in urban areas that are not as green, a new study shows.
The findings held up even when results were adjusted for factors such as neighborhood income, exposure to air pollution, noise, and neighborhood walkability, according to researchers at Oregon State University and the University of British Columbia.
“This was a surprise,” said Dr. Perry Hystad, an environmental epidemiologist in the College of Public Health and Human Sciences at Oregon State and lead author of the study. “We expected the association between greenness and birth outcomes to disappear once we accounted for other environmental exposures such as air pollution and noise. The research really suggests that greenness affects birth outcomes in other ways, such as psychologically or socially.”
Researchers aren’t sure yet where the link between greenness and birth outcome is. More study is needed to determine if additional green space provides more social opportunities and enhances a person’s sense of belonging in the community, or if it has a psychological effect, reducing stress and depression, Dr. Hystad said.
In a study of more than 64,000 births, researchers found that very pre-term births were 20 percent lower and moderate pre-term births were 13 percent lower for infants whose mothers lived in greener neighborhoods.
They also found that fewer infants from greener neighborhoods were considered small for their gestational age. Babies from the greener neighborhoods weighed 45 grams more at birth than infants from less green neighborhoods, Dr. Hystad said.
The study establishes an important link between residential “greenness” and birth outcomes that could have significant implications for public health, said Dr. Hystad, an assistant professor of environmental and occupational health.
“From a medical standpoint, those are small changes in birth weight, but across a large population, those are substantial differences that would have a significant impact on the health of infants in a community,” Dr. Hystad said.
Babies born early or underweight often have more health and developmental problems, not just at birth but also as they continue to grow up, and the cost to care for pre-term and underweight infants also can be much higher, Dr. Hystad said.
Results of the study were published recently in the journal “Environmental Health Perspectives.” Co-authors were Drs. Hugh W. Davies, Lawrence Frank, Josh Van Loon, Lillian Tamburic and Michael Brauer of the University of British Columbia; and Ulrike Gehring of Utrecht University in The Netherlands. The research was supported by a grant from Health Canada.