Study Air pollution could be linked to low birth weight in new-born babies, says research
Mothers who breathe the kind of pollution emitted by vehicles, coal power plants and factories are significantly likelier to give birth to underweight children than mothers living in less polluted areas, according to international findings.
The study is believed to be the largest to examine how newborns’ bodies are affected by air quality, an issue that has raised particular concern in China and other developing nations.
Nearly 30 researchers, including three from the Bay Area, based their conclusions on more than 3 million births at 14 sites in North America, South America, Europe, Asia and Australia.
Focusing on children born on-time in the mid-1990s to mid-2000s, they found that, worldwide, the greater the air pollution, the less babies tend to weigh at birth.
Weighing less than 5.5 pounds at birth is a factor for chronic health issues in childhood, including a higher risk for infection and developmental delays, experts say. Problems in adulthood can include cardiovascular disease, diabetes and other metabolic disorders.
“Being low-birth weight basically is like you’re starting at a little bit of disadvantage in terms of health throughout your lifetime,” said Tracey Woodruff, the study’s co-principal investigator and director of UCSF’s Program on Reproductive Health and the Environment.
For the study, researchers looked at two types of air pollutants, including inhalable coarse particles, which are about 10 micrometers in diameter and often appear in natural elements such as dirt, dust and sea salt.
The particles were found in various levels throughout the 14 sites. “The research showed that infants’ risk of having a low birth weight rose by 3 percent with every increase of 10 micrograms per cubic meter in inhalable coarse particles. Overall, with each increase, infants were born 3 grams lighter.
When the study factored in individual variables, such as the mother’s age and tobacco use, the average weight drop tripled to 9 grams.
The effect appeared to be even more dramatic with another type of air pollutant, fine particles. These are 2.5 micrometers in diameter and can come from forest fires, power plants, factories and cars.
Air pollution may have a small impact on an individual mother and her child. But in a large population, it could lead to a significant increase in the number of low birth-weight births, Morello-Frosch said.
The onus is on policymakers, not on mothers, to improve conditions, researchers said.