Baby's first stool may provide clues to fetal alcohol exposure, WSU School of Medicine study finds
Fetal alcohol exposure is usually determined through self-reported maternal consumption, an often unreliable measure that can lead to detrimental delays in identifying and treating children who are affected by fetal-alcohol syndrome. But Wayne State University School of Medicine researchers have found that the presence of certain fatty acid ethyl esters (FAEEs) in a baby's first stool may provide a dependable biomarker of fetal alcohol exposure.
Results are published in the July 2006 issue of Alcoholism: Clinical & Experimental Research .
"There are only a few biomarkers that indicate if an infant has been exposed to alcohol during pregnancy, and most of them are not strictly associated with alcohol use," said Enrique M. Ostrea, Jr., professor of pediatrics at Wayne State University . "In this study, we have found a direct association between the presence of certain FAEEs and alcohol use." Dr. Ostrea is also the corresponding author for the study.
When people drink alcohol, it combines with certain fats in the body known as fatty acids, and FAEEs are formed. These "markers" are either deposited in tissues or, in the case of a growing fetus, in fetal urine or meconium, a baby's first stool.
"People characteristically underreport the amount of alcohol they drink," said Michael Laposata, director of clinical laboratories at the Massachusetts General Hospital and professor of pathology at Harvard Medical School . "One can measure blood alcohol but it disappears from the blood relatively quickly after drinking stops, so only very recent intake can be documented. FAEEs are 'long-term markers' of alcohol intake because they stay much longer in blood than alcohol itself and, in this case, accumulate in meconium."
For this study, researchers examined 124 mother/infant pairs. Based on self reports, 93 of the mothers had consumed alcohol during pregnancy, and 31 had not. FAEEs were analyzed in the infants' meconium by a highly sensitive and specific method called positive chemical ionization gas chromatography/mass spectrometry. Results were correlated to maternal alcohol use during pregnancy.
The presence of FAEE ethyl linoleate in meconium is highly indicative of fetal exposure to alcohol during pregnancy, Dr. Ostrea said. The incidence of ethyl linoleate in meconium was found to be significantly higher in the alcohol-exposed group when compared to the control group. There was also a significant association between alcohol exposure and group concentrations of ethyl linoleate. Furthermore, the highest ethyl-linoleate concentration was only found in the alcohol-exposed infants.
Dr. Ostrea said the results also suggest that FAEEs ethyl arachidonate and docosahexanoate may have potential as biomarkers of alcohol effects on the developing fetal brain. Because these FAEEs are key to the formation of certain compounds required in retinal and brain development, alcohol exposure may interfere in the synthesis of these compounds, potentially resulting in mental retardation.
"This is an important report," said Laposata. "The measurements of the FAEEs are exceedingly well done. However, the test is only able to identify about one quarter of the mothers who ingest alcohol during pregnancy."
He suggested that testing expectant mothers for alcohol intake prior to delivery would have more merit than testing meconium after birth because an objective identification of alcohol intake during pregnancy could lead to intervention, possible cessation of drinking and a better outcome for the fetus. "We have an obvious need to check mothers during pregnancy before damage to the fetus is done," he said.
Until that transpires, Dr. Ostrea said, "Our manuscript is supportive of the validity of using FAEEs as biomarkers of prenatal alcohol exposure. This would allow early identification and treatment for children born with fetal alcohol effects who might otherwise not be recognized, particularly if the mother does not admit to drinking."
Alcoholism: Clinical & Experimental Research is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the paper, "Fatty acid ethyl esters in meconium: Are they biomarkers of fetal alcohol exposure and effect?," were: Joel D. Hernandez, Dawn M. Bielawski, Jack M. Kan, Gregorio M. Leonardo, Michelle Buda Abela, Michael W. Church, John H. Hannigan, Robert J. Sokol, James J. Janisse and Joel W. Ager. The study was funded by the National Institute on Alcohol Abuse and Alcoholism.