Womb pollution?

If you're pregnant and living in one of our many cities with unacceptable air quality, consider this: A study released last June by the Columbia University Center for Children's Environmental Health demonstrates that developing fetuses are more susceptible to DNA damage caused by combustion-related pollutants than their mothers are, despite protection by the placenta.

"These results raise serious concern," says Frederica P. Perera, director of the center and leader of the study. "Fetal susceptibility to DNA damage from air pollution, including motor vehicle emissions and secondhand smoke, has important implications for cancer risk and developmental problems. And it underscores the importance of reducing levels of air pollution."

The study, which began in 1998 in New York City, examined 256 nonsmoking African-American and Latina women and their newborns. Researchers sampled blood from the mothers and umbilical cords to evaluate the presence of two biomarkers--one associated with increased cancer risk, the other a measure of exposure to combustion-related pollutants.

"These exposures are damaging in terms of fetal growth," Perera says. "Reductions of this type have been associated in many other studies with reductions in cognitive development, learning and health."

Separate studies have shown that the placenta protects the fetus by reducing exposure to one-tenth of the mother's exposure. Despite such protection, the recent study showed similar levels of DNA damage between mothers and newborns. Levels of cotinine, which measures tobacco smoke exposure, were higher in newborns than in mothers.

"Women know they should not be smoking while pregnant, but they should also avoid secondhand smoke," Perera says. Reducing exposure to secondhand smoke can reduce the prevalence of these biomarkers, but it's not the only necessary measure. The biomarkers indicate exposure to combustion-related pollutants, including vehicle exhaust and emissions from residential heating and power generation.

"The Bush administration has essentially cut a big break for the big polluters and not enforced the Clean Air Act," says Frank O'Donnell, former executive director of Clean Air Trust. "In the meantime, the problem continues."

Exposure to these factors is more difficult for an individual to control than secondhand smoke, but is just as dangerous. "We need to take much more aggressive action to attack pollution at the source," O'Donnell says.

Dr. Norman H. Edelman, a consultant with the American Lung Association, says the new study is important "because it points out that the fetus inutero is far more at risk from air pollution than we have thought in the past. Despite the fact that the placenta filters out some of the poison, the fetus is especially sensitive and at risk."

While the release of these findings might serve as a wake-up-call to New York City, the results are not new, or surprising. In the 1990s Perera and her colleagues studied biomarker levels in mothers and newborns in Krakow, Poland. The results indicated the susceptibility of the fetus to contaminants. Pollution levels at that time were approximately 30 times greater in Krakow than in New York City. The new study shows that these dangers exist even in areas with lower concentrations of pollution.

Perera says the ability to identify the earliest sources of impairment will help lead to the creation of prevention strategies. "We can ultimately make a difference in reducing the burden of disease," Perera says. CONTACT: Columbia University Mailman School of Public Health, [phone], www.mailman. hs.columbia.edu; or visit http://ehp.n iehs.nih.gov to read the study.