Cord serum cotinine as a biomarker of fetal exposure to environmental tobacco smoke

OBJECTIVE: To compare the results obtained from pregnant mothers’ self-reports of smoke exposure with those obtained from laboratory tests of fetal cord blood.

METHODS: This cross-sectional study was conducted in Al-Elwyea Maternity Teaching Hospital, Baghdad, Iraq. Eighty-eight mothers and their newly born babies were included in the study through convenient sample techniques from August to November 2008. Information was obtained from the mother, and cord serum cotinine was analyzed using the enzyme linked immunosorbent assay method.

RESULTS: The calculated mean nicotine level according to mothers’ self-report was 4.267+/-2.557 ng/ml, while the mean cotinine level was 8.10+/-1.925 ng/ml. There was a linear relationship between nicotine level and laboratory levels of cotinine, and the correlation was strong (r=0.8043, p<0.0001). The equation y = 1.1912 x -5.3814 could be used to estimate approximate exposure to environmental tobacco smoke among nonsmoker pregnant women using self-reported information given by the nonsmoker pregnant mother.

CONCLUSION: Information on second hand smoke exposure provided by pregnant women is helpful, and can be used when cotinine level estimation is not available.