Fetal exposure to ethanol: relationship between ethyl glucuronide in maternal hair during pregnancy and ethyl glucuronide in neonatal meconium

Background: In recent years, fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG) in meconium emerged as reliable, direct biological markers for establishing gestational ethanol exposure. We investigated whether EtG in maternal hair measured during the three trimesters of pregnancy correlated with EtG and FAEEs in neonatal meconium. Methods: In a prospective sample of 80 mother-infant dyads from Barcelona (Spain), we measured EtG and FAEE in maternal hair segments and meconium samples using a validated UHPLC-MS/MS method. Results: Fifty-eight (72.5%) women had EtG concentrations in the hair shafts >7 pg/mg in one or more pregnancy trimesters, and EtG and FAEEs in meconium samples were documented in 50 and 24 of their neonates, respectively. The best significant correlations (p < 0.0001) were found between EtG concentration in the proximal 0-3 and 3-6 hair shaft segments corresponding to the last two pregnancy trimesters and EtG in neonatal meconium (rho = 0.609 and rho = 0.577, respectively). Using the combination of EtG in meconium >= 30 ng/g and a median of EtG > 11 pg/mg in maternal hair during the second and third trimesters of pregnancy, prenatal ethanol exposure could be predicted with a sensitivity of 85.7% and specificity of 73.7%. Conclusions: This study provides evidence of proven fetal exposure to ethanol during the second and third trimesters of pregnancy by linking detection of ethanol biomarkers (EtG) in maternal hair segments and EtG in neonatal meconium.