A groundbreaking new study shows an unborn baby’s risk of autism increases significantly if the child’s mom lives in an area high in air pollution while she is pregnant.
The nationwide study shows why the pollution may increase risk, when during pregnancy it is most dangerous and what type of pollution is worst.
Conducted by researchers at Harvard School of Public Health, the study looked at the children of 116,000 female nurses before, during and after pregnancy, beginning in 1989. The authors found pollution impacted the risk of autism in all children, with the risk was even greater for boys.
Dr. Heather Volk of Children's Hospital Los Angeles said the worst part of the pollution may be the tiny particles it contains.
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"The particles examined in this study are incredibly small. You don't see them, but they are easy to enter the body. They can be breathed in and ingested in other manners," she said.
Another significant finding of the study is that the danger is worst in the last trimester, when the unborn baby's brain is developing.
"It might change how cells in the brain grow and develop or transmit signals from cell to cell," Volk said. And that could be key to the risks of autism.
The study also confirmed danger existed even on days when the pollution is not visible.
The findings raise concerns for mothers.
"Definitely we're worried about that as moms and pregnant moms all the time," said Jennifer Duerksen, mother of two healthy children, who lives in the Los Angeles area.
Most families won’t move away from home because of the new study, and medical experts said the pollution is just one factor in whether or not a child could develop autism.
Duerksen said she has always tried to protect her kids.
"I'll just do my best to keep my kids away from smoke and any kind of dangerous chemicals and pollutants," she said.
Dr. Bruce’s advice: Have kids avoid smoke, make sure they get exercise and spend time in well-ventilated areas and stay indoors on days of high pollution.