LOS ANGELES, CALIFORNIA. Studies carried out in China, Brazil and Mexico have found a significant association between air pollution and low birth weight, preterm birth, and fetal mortality. Researchers at the University of California now report a strong correlation between exposure to carbon monoxide and ozone and defects in the hearts of newborn babies. Carbon monoxide and ozone are major pollutants generated by automobile traffic. The researchers correlated the levels of pollutants with birth outcome for almost 10,000 women living within 10 miles of an air monitoring station in Los Angeles. They found that women exposed to high levels of carbon monoxide and ozone in their second month of pregnancy were almost three times more likely to give birth to a child with certain heart anomalies (pulmonary artery and valve anomalies and ventricular septal defects) than were women who had been exposed to lower levels of the two pollutants. The researchers point out that the heart of the fetus develops during the second month of pregnancy and conclude that air pollution in southern California may contribute to heart-related birth defects.
Ritz, Beate, et al. Ambient air pollution and risk of birth defects in southern California. American Journal of Epidemiology, Vol. 155, January 1, 2002, pp. 17-25