[Implications of nicotine detected in autopsy cases of newborn babies and infants from the perspective of social medicine].

Smoking by pregnant and parturient women is generally suspected to increase nicotine levels in fetal and infant blood. Supportive data of nicotine levels in infants is, however, inadequate. We investigated blood and muscle nicotine and cotinine levels in 14 autopsy cases of newborn babies and infants using gas chromatography. Among the 14 cases investigated, nicotine or cotinine was detected in six cases (42.9%). In each of these six cases, the mother was a smoker. Route of exposure to nicotine originating from smoking was transplacental in three cases, via breast milk in one case and secondhand smoke in two cases. Nicotine and cotinine levels in blood from the two cases with placental exposure were 10.6-84.4 ng/ml and 20.3-183 ng/ml, and levels in muscle from one case were 43.9 ng/g and 308 ng/g, respectively. Nicotine and cotinine levels in blood from exposure via breast milk were 19.1 ng/ml and 87.1 ng/ml, and from secondhand smoke were 0 ng/ml and 14.6-20.1 ng/ml. Mean concentrations of blood nicotine and cotinine in 68 autopsy cases of adult habitual smokers were 30.0 ng/ml and 247 ng/ml. Our data for nicotine and cotinine levels in infant blood seem to indicate that some infants who are born and develop under exposure to smoking by family members, particularly the mother, may show high nicotine levels in blood and experience possible health risks.