Pubdate: Monday, 24 August, 1998 Source: Standard-Times (MA) Contact: http://www.s-t.com/ Author: Michael Woods, Toledo Blade PREGNANT SMOKERS TRANSMIT TOXINS BOSTON -- Women who smoke cigarettes during pregnancy transmit one of the most powerful carcinogens in tobacco smoke straight to the blood of their unborn babies, scientists reported here yesterday. Until now, public health authorities believed that nicotine and carbon monoxide were the two most dangerous substances passed from the blood of smoking mothers through the placenta into the blood of a developing fetus. Carbon monoxide decreases the amount of oxygen circulating inside the fetus' body. Nicotine, which is highly addictive, has its own adverse effects. Both substances got much of the blame for rouge's gallery of harmful effects linked known to occur in babies born to smoking mothers. "This represents an unacceptable new risk to the fetus," Dr. Stephen S. Hecht said in an interview. "Women should make every effort to not to smoke during pregnancy, or any other time, for that matter." Dr. Hecht reported the first direct chemical evidence that a powerful tobacco carcinogen, NNK, is transmitted to the developing fetus when a woman smokes cigarettes. He announced the finding at the 216th national meeting of the American Chemical Society (ACS), being held here this week. With 155,000 members, the ACS is the world's largest scientific organization. About 14,000 members are gathering here to present and hear 6,700 reports on new advances in scientific fields -- ranging from astronomy to zoology that involve chemistry. In addition to holding national meetings, the ACS publishes most of the world's top chemistry journals, sets standards for chemical names and education, and engages in other activities. Smoking is surprisingly common among pregnant women, Dr. Hecht noted. Tobacco smoke contains more than 2,500 chemical compounds, including about 40 carcinogens, substances that cause cancer. Dr. Hecht and his associates detected NNK and related compounds in urine samples collected from newborn infants whose mothers smoked during pregnancy. No NNK was found in urine of infants born to non-smoking mothers. Since the carcinogen is found only in tobacco smoke, there was no other possible way, aside from cigarette smoking, in which it could have gotten into the infants' bodies, Dr. Hecht said. Researchers do not know whether NNK, like nicotine, also is passed to infants in the breast milk of smoking mothers who nurse, Dr. Hecht said. Women who smoke have a higher risk of complications during pregnancy, low birthweight babies, stillbirths, and more babies who die during the first month of infancy, according to the American Cancer Society. The society said studies also link smoking during pregnancy with long-term effects on a child. At age 7, for instance, children whose mothers smoked heavily during pregnancy were shorter in stature and had lower reading ability than other children. Dr. Hecht said the precise risks to unborn infants from NNK are not yet clear. One major concern involves the possibility that infants exposed to such a carcinogen before birth may have an increased of cancer as adults, he said. The cancer society says that children exposed to 10 or more cigarettes during pregnancy have a 50 per cent higher risk of cancer. - --- Checked-by: Patrick Henry