Hair and nail nicotine levels of mothers and their infants asvalid biomarkers of exposure to intrauterine tobacco smoke
Mitzi Go, Wael K. Al‐Delaimy, Diane Schilling, Brittany Vuylsteke, Shawn Mehess, Eliot R. Spindel, Cindy T. McEvoy
Abstract
on growth, lung development, asthma, postnatal infections and sudden infant death syndrome (SIDS) Numerous reports have also established that maternal tobacco smoking during pregnancy is associated with increased risks for adverse maternal conditions (e.g. premature rupture of membranes, abruptio placenta, and placenta previa) and adverse pregnancy outcomes (e.g. neonatal mortality and stillbirth, preterm ABSTRACT INTRODUCTION Tobacco use remains the single most modifiable cause of adverse pregnancy outcomes. It is crucial to be able to accurately quantify the burden of tobacco exposure on both the mother and fetus to have better measures of efficacy with interventions being studied. METHODS This is a descriptive and exploratory study conducted within a randomized controlled trial. Pregnant smoking and non-smoking women were followed from 22 weeks' gestation through delivery with monthly maternal smoking questionnaires, urine cotinine levels, and collection of maternal and infant hair and nail samples, at delivery. Nicotine was extracted and measured (ng/mg) using high-performance liquid chromatography with electrochemical detection. RESULTS Forty-six mother-infant dyads (34 pregnant smokers and 12 pregnant non-smokers) had successful completion of maternal and infant hair and nails samples. The median hair nicotine levels of the smoking mothers and their infants was significantly higher than those of the non-smokers (1.015 vs 0.037 ng/ mg, p<0.05 for the mothers; 0.445 vs 0.080 ng/mg, p<0.01 for the infants). Similarly, the median nail nicotine levels for smoking mothers and their infants were significantly higher than the non-smokers (2.130 vs 0.056 ng/mg, p<0.01 for the mothers; 0.594 vs 0.132 ng/mg, p<0.05 for the infants). We found a moderate but significant correlation between maternal hair and nail nicotine (r=0.64, p<0.001), infant hair and nail nicotine (r=0.64; p<0.001), maternal and infant hair nicotine (r=0.61, p<0.001), and maternal and infant nail nicotine levels (r=0.58, p<0.001). CONCLUSIONS Our study shows that both infant hair and nail nicotine levels are valid biomarkers of intrauterine tobacco smoke exposure, and can be used to identify prenatal smoke exposure, correlating well with the level of maternal nicotine exposure.