Pregnant smokers have run out of excuses

日期:2017-12-03 01:15:47 作者:秋燹掀 阅读:

By Lila Guterman BABIES whose mothers smoke during pregnancy are born with a carcinogen in their bodies, say chemists in the US. For the first time, a cancer-causing substance from tobacco has been detected in newborn infants’ urine. It was already known that babies born to mothers who smoke during pregnancy tend to be small and may have chromosomal irregularities (New Scientist, Science, 1 April 1995, p 20). But until now, little has been known about whether the fetus absorbs carcinogens. Chemist Stephen Hecht and his colleagues at the University of Minnesota Cancer Center in Minneapolis analysed urine from 48 newborn babies for metabolites of a compound called NNK, or 4-methylnitrosamino-1-(3-pyridyl)-1-butanone. NNK is a potent carcinogen that causes lung cancer in rodents. It is found only in tobacco smoke. The team used the highly sensitive techniques of gas chromatography and mass spectroscopy to measure NNK metabolites. Hecht told this week’s meeting of the American Chemical Society in Boston that his team found no NNK metabolites in any of the samples from the 17 newborns whose mothers did not smoke. But in 22 of 31 babies born to smoking mothers, they found levels as high as a tenth of those found in adult smokers. Hecht says the fetus gets NNK from its mother through the placenta. This continues throughout pregnancy as the fetus grows and develops. “These are significant exposures to toxic compounds that present unacceptable risks,