[Concentrations of cotinine in serum and urine of smoking pregnant women and in placenta and umbilical cord blood].

Concentration of cotinine, the major metabolite of nicotine in body fluids, is commonly accepted as the method which may better reflect tobacco smoke exposure than the questionnaire. In order to assess adverse fetal health effects caused by cigarette smoking it is important to study the relation between maternal and fetal exposure to tobacco smoke compounds. We determined serum and urine cotinine levels in the course of pregnancy, as well as its concentration in placenta and umbilical cord blood. In group of smoking women serum cotinine concentration was high (above 1050 microg/l) and stable in I, II and III trimester. It was correlated with amount of cotinine (about 2000 microg/g creatinine) in urine (r=0.8; p<0.0001). In serum of umbilical cord blood level of cotinine was half (range: 300-600 microg/ I) of that observed in maternal blood and was correlated with it (r=0.67; p<0.01). In placenta of smoking women mean concentration of cotinine was 57.5 ng/g tissue. In serum of non-smoking pregnant women and in blood of their babies we found trace amount of cotinine in 50% of mothers and 30% of infants. In this group concentration of cotinine in urine as well as in placenta was not detectable. The obtained results indicate that assay of cotinine by specific and inexpensive methods may be useful for monitoring of exposure to tobacco smoke both of mothers and newborns.