Characterization of 4-aminobiphenyl-hemoglobin adducts in maternal and fetal blood-samples

The maternal-fetal exchange of the potent tobacco-related human carcinogen 4-aminobiphenyl was studied in women smokers during pregnancy. The number of cigarettes smoked per day by each of the women in the study was assessed via questionnaire and by measurement by immunoassay of serum and urine cotinine in maternal and fetal blood samples. Maternal and fetal blood samples were classified as coming from nonsmokers (n = 74), individuals smoking less than 1 pack of cigarettes per day (n = 16), individuals smoking 1 pack of cigarettes per day (n = 19), individuals smoking 1-2 packs of cigarettes per day (n = 19), and individuals smoking greater than 2 packs of cigarettes per day (n = 20). Both maternal and fetal blood samples were obtained at the time of delivery. 4-Aminobiphenyl was extracted from both maternal and fetal blood samples using organic extractions and the released amine was qualitatively and quantitatively characterized by analysis of the samples by gas chromatographic and mass spectrometric analysis. Background levels of 4-aminobiphenyl-hemoglobin adducts were detected in maternal nonsmokers (18.3 +/- 12.7 pg 4-aminobiphenyl/g hemoglobin, mean +/- SD) and in fetal samples (8.88 +/- 5.8 pg/g hemoglobin). Increasing levels of 4-aminobiphenyl-hemoglobin adducts were found as the smoking status of the women increased, ranging from 144 +/- 22.2 ( < 1 pack/d) to 633 +/- 87.9 ( > 2 packs/d). A corresponding increase in the presence of fetal 4-aminobiphenyl-hemoglobin adducts was also detected (74 +/- 17.8, < 1 pack/d, to 319 +/- 50.5, > 2 packs/d). This study confirms that the potent tobacco-related carcinogen 4-aminobiphenyl crosses the human placenta and binds to fetal hemoglobin in significantly higher concentrations in smokers when compared to nonsmokers.