Detection of in utero ethanol exposure via ethyl glucuronide and ethyl sulfate analysis in umbilical cord and placenta

Abstract

Alcohol exposure during pregnancy constitutes one of the leading preventable causes of birth defects, mental retardation and neurodevelopmental disorders in the exposed children. The ethanol marker ethyl glucuronide (EtG) is a specific long-term marker of ethanol in utero exposure in meconium; however, currently, there are scarce or no data about EtG and ethyl sulfate (EtS) in umbilical cord and placenta. These tissues are alternative matrices to meconium that offer critical advantages, such as always being available at birth with noninvasive and easy collection. We developed and validated a method for the determination of EtG and EtS in umbilical cord and placenta. Tissues were homogenized in methanol, extracted using weak anion-exchange solid-phase extraction (SPE) and analyzed by liquid chromatography–tandem mass spectrometry. The umbilical cord and placenta method was applied to 59 authentic samples from newborns whose meconium samples were positive for EtG (EtG > 5 ng/g). The method in umbilical cord and placenta was fully validated, with a limit of quantification at 5 ng/g in umbilical cord and 10 ng/g in placenta for both compounds. EtG and/or EtS were detected in 25 umbilical cord samples (4.4–529 and 4.3–39 ng/g, respectively) and in 8 placenta samples (26.5–267 and 11–24.3 ng/g, respectively). EtG and EtS showed a homogenous distribution throughout umbilical cord tissue (n = 5). We developed and validated a sensitive and specific method for the determination of EtG and EtS in umbilical cord and placenta. To date, this is the first method to investigate both direct metabolites of ethanol in umbilical cord and placenta samples for prenatal ethanol exposure.