THE EFFECTS OF MATERNAL CIGARETTE-SMOKE EXPOSURE ON SOMATIC MUTANT FREQUENCIES AT THE HPRT LOCUS IN HEALTHY NEWBORNS

We utilized the hprt T-cell cloning assay to prospectively determined the somatic mutant frequency at the hprt locus of fetal T-lymphocytes exposed in utero to maternal active and passive cigarette smoke. In ad dition, a maternal questionnaire was administered to evaluate a number of social and medical parameters that may effect hprt mutant frequenc y. Newborn cord blood plasma cotinine levels were determined on all su bjects to compare in utero tobacco metabolite levels with maternal smo king histories. A total of 63 newborns were enrolled and placed into f our groups: Group I (n = 21), newborns whose mothers had no history of active or passive cigarette exposure during the pregnancy; Group II ( n = 12), newborns whose mothers actively smoked cigarettes throughout the pregnancy; Group III (n = 8), newborns whose mothers actively smok ed cigarettes during first trimester only; and Group IV (n = 22), newb orns whose mothers were exposed only to passive cigarette smoke. Our a nalysis showed no statistically significant difference in hprt mutatio n frequency between any of the four groups, A significant increase in plasma cord blood cotinine was detected in Group II, newborns whose mo thers were active cigarette smokers throughout the pregnancy. Our data indicate that exposure to active and passive maternal cigarette smoke in utero does not result in a significant increase in somatic mutant frequency as determined by the hprt T-cell cloning assay.