Breathing Smog in Pregnancy Linked to Child's Behavior
THURSDAY, March 22 (HealthDay News) -- Women exposed to higher
levels of certain air pollutants while pregnant are more likely to
have children with anxiety, depression and attention problems by
ages 6 and 7, new research suggests.
"This study provides new evidence that prenatal exposure to air pollution at levels encountered in New York City can adversely affect child behavior," said Frederica Perera, a professor of environmental health sciences and director of the Columbia Center for Children's Environmental Health at the Columbia University Mailman School of Public Health.
She led the new study, published online March 22 in
Environmental Health Perspectives.
The researchers looked at pollutants known as polycyclic
aromatic hydrocarbons (PAH). They are created by the burning of
fossil fuels and are common in urban environments. Traffic
emissions are a major source of these pollutants.
The study is believed to be the first to link behavior problems
in school-age children with two measures of prenatal PAH exposure:
air concentrations and a PAH-specific marker found in mothers'
blood samples and umbilical cord blood. The PAH, inhaled by the mom
during pregnancy, can cross the placenta, experts know.
Perera's team followed the children of 253 inner-city women who
gave birth between 1999 and 2006. None of the mothers smoked.
The researchers measured the concentrations of PAH in the
environment of the mothers for 48 hours during trimester two or
three. They also took blood samples from the mothers and the
In addition, the women answered questions about their children's
behavior, including describing any attention problems, anxiety or
depression. The attention problems would not qualify as
attention-deficit/hyperactivity disorder, Perera noted.
The investigators found a link between higher PAH exposure
levels and behavior problems. "Symptoms of anxiety and depression
were 45 percent higher in the higher exposure group versus the
lower," Perera said. Attention problems were 28 percent greater in
the higher PAH exposure group.
When the researchers took into account other sources of
pollutants such as tobacco smoke and diet, the link remained.
However, although the study found an association between prenatal
PAH exposure and childhood behavior problems, it did not prove a
The level of problems were those that could result in referral
to a doctor for further evaluation, Perera noted.
Several mechanisms could explain the link, she said. Oxidative
stress is one. Or, the chemicals may be "endocrine disrupters,
which are capable of affecting the normal signaling that occurs in
early brain development."
Perera plans to follow the children until they are age 12.
"The study by itself is not convincing to me," said Dr. Victor Klein, an obstetrician-gynecologist who specializes in high-risk pregnancies and is director of patient safety and risk reduction at North Shore-LIJ Health System in Great Neck, N.Y. He reviewed the study and said that "further research has to be done."
Meanwhile, Klein said, it's "common sense" to try to keep your
environment as pollution-free as possible, especially when
pregnant. However, that can be easier said than done. He tells
women to exercise, watch their diet and get good prenatal care.
Another expert, Dr. Andrew Adesman, chief of developmental and
behavioral pediatrics at the Steven & Alexandra Cohen
Children's Medical Center of New York in New Hyde Park, wondered if
the study would apply to pregnant women living outside New York
City. "On one hand, I don't think people will be surprised that
pollution poses a potential risk," he said. "What is striking here
is they have been able to document and quantify it."
The broader message, Adesman said, is the need for society to
clean up the air and to reduce our dependence on fossil fuels.
Perera said that to reduce exposure to pollutants, pregnant
women should not smoke and should ask others not to smoke in their
homes and offices. When cooking, she said, ventilate with a fan.
Avoid other toxic chemicals such as pesticides. And, in addition,
eat a healthy diet full of antioxidant-rich foods such as fruits
and vegetables, she advised.
To learn more about staying healthy during pregnancy, visit
womenshealth.gov from the U.S. Department of
Health and Human Services.
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