Tobacco-specific transplacental carcinogens, nicotine, and cotinine in theurine of newborns of smoking mothers

Background: Cigarette smoking is common during pregnancy and can expose the developing fetus to transplacental carcinogens, but relatively little info rmation is available on fetal uptake of such compounds. It was the aim of t he present study to analyze the first urine of newborns of mothers who did or did not smoke for metabolites of the tobacco-specific carcinogen 4-(meth ylnitrosamino)-1-(3-pyridyl)-1-butanone(NNK)as well as nicotine and cotinin e. Methods: First urine of newborns was collected and analyzed for two metabol ites of NNK. The metabolites are 4-(methylnitrosamino)-1 -(3-pyridyl)-1-but anol (NNAL) and its glucuronide, NNAL-Gluc. The analyses were carried out b y gas chromatography and nitrosamine-selective detection with confirmation by mass spectrometry. Nicotine and cotinine were analyzed by gas chromatogr aphy-mass spectrometry. Results: NNAL-Gluc was detected in 22 of 31 (71%) of the urine samples from newborns of smoking mothers; in 4 cases, NNAL was also detected. Neither o f these analytes was detected in the 17 samples from newborns of mothers wh o did not smoke. NNAL plus NNAL-Gluc levels in the positive quantified newb orn urine samples were 0.19+/-0.14 pmol/ml urine, about 10% of that seen in adult smokers. NNAL plus NNAL-Gluc levels correlated with the number of ci garettes smoked per day during pregnancy (r=0.55; p<0.005). Nicotine and co tinine levels in the urine of newborns of smoking mothers were also signifi cantly higher than in the urine of newborns of non-smoking mothers and corr elated well with levels of NNAL plus NNAL-Gluc. Conclusions: The results demonstrate that two metabolites of the tobacco-sp ecific transplacental carcinogen NNK are present in the urine of newborns b orn to mothers who smoke cigarettes.