Ethyl linoleate in meconium: A biomarker for prenatal ethanol exposure

Background: Fetal alcohol syndrome, fetal alcohol effects, alcohol-related neurodevelopmental disorder, and alcohol-related birth defects, all terms referring to the spectrum of consequences of in utero exposure to ethanol, are a major public health burden. There is currently no laboratory test to identify newborns exposed to ethanol in utero. Meconium was analyzed for ethyl linoleate, a metabolite of ethanol, as a biological marker for fetal ethanol exposure. Methods: Samples of meconium were obtained from 248 infants and analyzed for fatty acid ethyl esters. Detailed maternal alcohol, tobacco, and drug use histories were obtained within 1 month of giving birth. Results: The detection of ethyl linoleate in meconium was called a positive test. The mean number of drinks reported per week in the month before pregnancy, the first trimester, and overall were significantly higher in the positive group (unadjusted: 9.2 +/- 1.9 vs. 4.3 +/- 1.4, p = 0.004; 7.3 +/- 1.7 vs. 3.8 +/- 1.2, p = 0.03; and 6.1 +/- 1.3 vs. 3.0 +/- 1.0, p = 0.006). A positive test was not associated with marijuana, cocaine, or tobacco use. Sensitivity and specificity of the test were 72% and 51% to distinguish women who reported 1 or more drinks/week in the third trimester from women who denied use, and 68% and 48% to distinguish women who used greater than or equal to 1 drink/week from women who used <1 drink/week in the month before pregnancy. Conclusions: The presence of ethyl linoleate in meconium is the first reported biological marker for maternal ethanol use during pregnancy. Because of the inherent inaccuracy associated with the use of self-reporting, the establishment of true values of sensitivity and specificity will require validation where the presence, quantity, and timing of exposure to alcohol is known. Further validation of this marker will permit identification and intervention of at-risk infants.