Characterization of phosphatidylethanol blood concentrations for screening alcohol consumption in early pregnancy

Abstract

Objective. Phosphatidylethanol (PEth) is formed endogenously by the direct action of ethanol, and has a half-life long enough to make it a reliable biomarker of alcohol exposure in early pregnancy. In this study, we aimed to characterize PEth blood concentrations to differentiate different levels of alcohol exposure in pregnant women. Methods. The study consisted of 305 consecutive pregnant women who had been referred to our hospital for antenatal care. Of them, 117 self-reported alcohol ingestion in the first trimester of pregnancy and 188 were abstainers. Total PEth concentration in whole blood was quantified by liquid chromatography-mass spectrometry (LC-MS/MS). Alcohol ingestion was classified according to the United States National Institute on Alcohol Abuse and Alcoholism into light drinkers: ≤ 3 drinks/week, moderate drinkers: 3–7 drinks/week, and heavier drinkers: > 7 drinks/week (a standard drink = 14 g of ethanol). Results. Participants had quantifiable PEth blood levels 3–4 weeks after the last drink. There were 4.8% abstainers who had positive PEth concentrations; all of them reported a positive history of alcohol consumption before conception. PEth blood concentrations were significantly correlated to drinks per occasion (r = 0.44; P < 0.001) and days drinking per week (r = 0.34; P < 0.001). However, almost 74% of participants with ≤ 3 drinks/week of alcohol, and 46% with 3–7 drinks/week, had PEth blood concentrations below the lower limit of quantification (LLOQ). The area under the curve (AUC) generated by a receiver operation characteristic curve (ROC) analysis increased as the cutoff value of PEth blood concentration increased. However, the cutoff values were below or close to the LLOQ. Conclusions: Our study presents a formal characterization of PEth blood concentrations for screening alcohol ingestion in first-trimester pregnant women. However, caution is recommended for overrepresenting either negative or positive results.

Keywords:

• Biochemical markers
• Ethanol
• Pregnancy