因为怀孕时接触过污染的环境，有出生缺陷的孩子越来越多。有证据表明，空气污染也能引发出生缺陷。准备养育下一代的父母注意了，一定要挑选一个干净无污染的环境哦。

Women exposed to air pollution during pregnancy are more likely to give birth to children with heart defects, researchers reported on Saturday. They said their study, published in the American Journal of Epidemiology, is the first definitively to link air pollution with birth defects.

“THERE SEEMS to be something in the air that can harm developing fetuses,” Beate Ritz, an epidemiologist who headed the study, said in a statement.

The team, at the University of California Los Angeles (UCLA) School of Public Health and the California Birth Defects Monitoring Program, said the two pollutants they measured were carbon monoxide and ozone - produced by the city’s well-known traffic jams.

“The greater a woman’s exposure to one of these two pollutants in the critical second month of pregnancy, the greater the chance that her child would have one of these serious cardiac birth defects,” Ritz said.

“More research needs to be done, but these results present the first compelling evidence that air pollution may play a role in causing some birth defects.”

Ritz’s team compared air pollution monitoring data from the Environmental Protection Agency with information from the California Birth Defects Monitoring Program - a statewide database on birth defects.

They looked at 9,000 babies born from 1987 to 1993. Pregnant women who were exposed to the highest levels of ozone and carbon monoxide because their homes were close to busy freeways were three times as likely to have a child with certain heart defects as women breathing the cleanest air.

The researchers said it was not certain carbon monoxide and ozone that were directly causing the defects. They could be a “marker” - something associated with the real cause.

But she said they were unable to evaluate other potential risk factors for birth defects, including smoking, occupational exposures, vitamin supplement use, diet and obesity.