Assessment of prenatal tobacco smoke exposure by determining nicotine and its metabolites in meconium

Abstract

<jats:p> Meconium samples collected from 115 neonates were analysed for nicotine, cotinine and trans -3-hydroxycotinine (OH-cotinine) by means of high-performance liquid chromatography (HPLC) to identify prenatal smoke exposure. The self-reported maternal smoking status during pregnancy was determined by means of a questionnaire and verified by measurements in urine prior to childbirth. The total sum of nicotine and its metabolites (Sum<jats:sub>tot</jats:sub>) of the first passed meconium samples was 1560 ± 1024 pmol/g in newborns of smoking mothers. Smoking of less than five cigarettes was clearly detected. Sum<jats:sub>tot</jats:sub> remained constant in all meconium samples passed by a neonate in succession. However, the proportion of nicotine decreased with the time of passage after birth and the OH-cotinine proportion increased, whereas cotinine hardly changed. Nicotine or its metabolites were not detectable in meconium (detection limit &lt; 20 pmol/g), when the mothers were only exposed to environmental tobacco smoke (ETS) using the HPLC method. The hypothesis that the content of nicotine metabolites in meconium reflects long-term smoke exposure could not be confirmed in newborns whose mothers had quit smoking during the latter half of pregnancy. Determining Sum<jats:sub>tot</jats:sub> enables the intensity of continuous smoking during pregnancy to be estimated in all meconium samples passed by a newborn. Human &amp; Experimental Toxicology (2007) 26: 535—544 </jats:p>

Nicotine and metabolites in meconium as evidence of maternal cigarette smoking during pregnancy and predictors of neonatal growth deficits

“…To our knowledge, only one other report has evaluated the relationship between the number of maternal cigarettes consumed daily and meconium concentrations, finding a moderate correlation (r = .492-.678) for nicotine, cotinine, OHCOT, and the summed meconium concentrations (Kohler et al, 2007). Despite finding statistically significant correlations in our data and those of Kohler, predicting the number of cigarettes with meconium concentrations would be difficult given the low correlation coefficients.…”

“…While others failed to observe nicotine or OHCOT in meconium (Baranowski, Pochopien, & Baranowska, 1998;Ostrea, Knapp, Romero, Montes, & Ostrea, 1994), previous data from our laboratory and others demonstrated that nicotine and OHCOT are as prevalent and abundant as cotinine (Gray, Magri, Shakleya, & Huestis, 2008;Kohler et al); moreover, an additional 25% of neonates were identified as tobacco exposed by including both nicotine and OHCOT in testing procedures (Gray, Magri, et al). However, in this cohort, the majority of meconium specimens contained all three tobacco biomarkers.…”

“…However, more recent research employing more sensitive analytic methodology suggest that active smokers can be differentiated from nonsmokers and environmentally exposed women, but nonsmokers and environmental-exposed women are indistinguishable based on meconium concentrations. Kohler et al (2007) clearly identified active smokers from environmentally exposed or nonsmokers, as all meconium specimens from the active smoking group were positive at a 20 pmol/g (~3 ng/g) analytic limit, whereas meconium specimens from environmentally exposed and nonsmoking groups were all negative. Similarly, our laboratory previously proposed a 10 ng/g nicotine, cotinine or OHCOT cutoff to differentiate active smokers from passive or nonsmokers (Gray, Magri, et al, 2008).…”

“…Previous studies investigating cigarette consumption have not reported specific relationships between number of cigarettes smoked per day and time elapsed between last cigarette and birth. Kohler, Avenarius, Rabsilber, Gerloff, and Jorch (2007) evaluated meconium results, maternal urine concentrations, and self-reported gestational age at smoking cessation among nine maternal/fetal dyads, yet no clear relationship between the time interval between smoking cessation and birth, presence of nicotine biomarkers in maternal urine at delivery, and positive neonatal meconium were noted.…”

“…Recently, researchers employed more sensitive and selective procedures allowing quantification of nicotine and its major metabolites, cotinine, and OHCOT in meconium Kohler et al, 2007). While others failed to observe nicotine or OHCOT in meconium (Baranowski, Pochopien, & Baranowska, 1998;Ostrea, Knapp, Romero, Montes, & Ostrea, 1994), previous data from our laboratory and others demonstrated that nicotine and OHCOT are as prevalent and abundant as cotinine (Gray, Magri, Shakleya, & Huestis, 2008;Kohler et al); moreover, an additional 25% of neonates were identified as tobacco exposed by including both nicotine and OHCOT in testing procedures (Gray, Magri, et al).…”