Newswise — A simple screening test could help identify infants at risk of fetal alcohol spectrum disorders (FASD), according to a report in the journal Alcoholism: Clinical and Experimental Research. Prenatal exposure to alcohol can cause a wide range of lifelong physical, behavioral, and cognitive disabilities, encompassed by the umbrella term FASD.Identifying babies at risk for FASD has previously relied on maternal self-reports of drinking in pregnancy; however, this can be unreliable, as women may under-report their drinking because of recall bias or fear of stigma. Recently, biological markers have been identified that can provide more objective data on prenatal alcohol exposure and supplement information from maternal self-reports. One such biomarker, phosphatidylethanol (PEth), is a direct marker of alcohol metabolism that can indicate exposure with a high level of accuracy, and can be simply measured in newborns (and their mothers) using minimally invasive methods.

In a new study, researchers from the US and Latin America measured levels of PEth in mothers and their infants and compared these with self-reported prenatal alcohol use. Over one thousand postpartum women from two maternity hospitals in Brazil and Uruguay agreed to participate. Within two days of giving birth, the mothers reported on their health behaviors during the pregnancy, including alcohol use, in interviews with a trained researcher. Blood spots for biomarker analysis were collected from them and their newborns, the latter during blood collection (through heel stick) for routine infant screening tests. The samples were then analyzed using methods that can detect very low levels of PEth. A positive test is indicative of alcohol exposure within the previous month (i.e within the last month of pregnancy). 

Most of the babies (87% of the Uruguayan and 77% of the Brazilian newborns) tested positive for PEth, as did up to half of their mothers (46% in Uruguay, 33% in Brazil). The average level of the biomarker in blood spot samples was also higher among the babies than their mothers, with 177 newborns, and 33 women, showing high concentrations of PEth suggestive of heavier or more frequent alcohol use. Reasons for the discrepancy between newborns and mothers are unclear, but may relate to metabolic differences in PEth formation and degradation in utero. The biomarker findings differed substantially from maternal interview data, with only 13% of mothers reporting alcohol consumption during the last trimester of pregnancy.

A clinical diagnosis of FASD is normally made in middle childhood, but routine measurements and vital signs at birth may be early indicators. In this study, babies with a positive PEth screen did not differ in weight, length, head circumference, or APGAR score from those with a negative sceen. Further studies will be needed to evaluate whether biomarker screening at birth can determine levels of risk for the later development of detrimental effects of alcohol exposure.

As the study was limited to only two hospitals, it does not provide a full picture of maternal alcohol use in Brazil and Uruguay. However, the biomarker data indicate that, in this particular study population, alcohol use during the final trimester of pregnancy was very common, despite only a minority of mothers reporting drinking during this period. The researchers propose that newborn PEth screening may be of value in such populations where prenatal alcohol use is common. Babies identified as at high risk for later diagnosis of FASD could undergo long-term monitoring and be referred for early intervention where warranted. There may also be a role for screening pregnant women using PEth, to supplement self-reported information on drinking and identify those who may benefit from referral to alcohol treatment programs. 

Phosphatidylethanol (PEth) Levels in Post-Partum Women and Their Newborns in Uruguay and Brazil. A. Baldwin, N. Hayes, E. Ostrander, R. Magri, N. Sass, M. dos Anjos Mesquita, M. Martínez, M.C. Juliani, P. Cabral, M. Fleming (pages xxx)