Double Dose of Bad Air Puts Fetuses
at Risk - The New York Times
January 27, 2004
Melissa P. McNamara
Combined exposure to secondhand smoke and urban air pollutants at levels
encountered in New York City can hurt fetal development, a study by the
Columbia Center for Children's Environmental Health says.
While previous research has explored the effect of secondhand smoke and
urban air pollution independently on fetuses, the study is the first to
a significant combined effect of both pollutants on birth weight and
circumference, two standard measures of fetal growth. Babies exposed in the
womb to both secondhand smoke and high levels of urban air pollutants
7 percent reduction in birth weight and a 3 percent reduction in head
circumference, scientists found, compared with babies exposed only to
levels of urban air pollution in utero.
The study is to be published in Environmental Health Perspectives in
"The effects we see, reduced fetal growth and lower birth weight, have
linked to later problems in learning and school performance in
said Dr. Frederica P. Perera, the senior author of the study and
the center. "These are warning signs that we should take seriously."
The findings are noteworthy because pollutants affect the human body
simultaneously, rather than separately, as they are frequently studied,
researchers say. The scientists also used a new approach to measure the
effects of pollutants on individual babies, by tracking the pollutants
DNA, Dr. Perera said.
The researchers conducted the study on 214 infants of nonsmoking
African-American and Dominican women in Washington Heights, Central
and the South Bronx, the communities the center serves. Members of urban
minority groups are also at high-risk for problem births and are more
to be exposed to environmental contaminants. But the findings can be
generalized across race and ethnicity, the researchers say.
The researchers examined the effect of prenatal exposure to two common
pollutants on fetal growth - environmental
tobacco smoke and
which enter the air from car, truck or bus
engines, residential heating and power generation.
Interviewers administered a 45-minute questionnaire to the participants
during the last trimester of pregnancy to track demographic information,
travel away from their homes in the past year, number of household
who smoke and alcohol use in each trimester.
When the women gave birth, the researchers compared those infants whose
mothers had lived in households where a smoker was present to those
mothers did not by measuring DNA damage caused by the pollutants in the
umbilical cord blood of the newborns.
The findings show the combined effect of these two exposures can damage
developing fetus, Dr. Perera said. Babies exposed to second-hand smoke
air pollutants were, on average, half a pound (or 233 grams) lighter and
their heads were almost half an inch (10 millimeters) smaller in
Dr. Perera said the results showed the need to improve air quality. "My
advice to pregnant women," he added, "is don't let people in your