Fetal ADH2*3, maternal alcohol consumption, and fetal growth.

There is some evidence suggesting the allele for alcohol dehydrogenase 23 (ADH23) is associated with a protective effect against alcohol-related intrauterine growth retardation (IUGR). This study was conducted to explore the affect of the ADH23 allele on fetal growth. Bloodspots (n = 1016) belonging to individual infants of a subgroup of the Baltimore-Washington Infant Study (BWIS) were assayed for the presence of the ADH23 allele by a polymerase chain reaction (PCR)-based method. Infants genotyped for ADH23 were those for whom bloodspots were identified and obtained from the Maryland Newborn Screening Program. The effect of ADH23 and maternal alcohol consumption on intrauterine growth was explored by multivariable linear regression analysis. Twenty-six percent of the 306 blood spots belonging to African-American infants were positive for ADH23 (4% were homozygous and 22% were heterozygous). Only a small percentage of bloodspots for Caucasian (1.3%) were positive for the ADH23 allele. Consequently, further analysis concentrated on gene-exposure interactions for African-American infants. It was found that the incidence of being small-for-gestation-age (SGA) was lower for ADH23-positive infants (2.5% versus 8.8%; p = .08). SGA infants had elevated odds for being ADH23 negative (OR: 3.15, 95% C.I.: 0.70-14.26) and for being born to mothers that consumed alcohol during pregnancy (OR: 2.31, 95% C.I.: 0.77-6.91). A negative trend between maternal alcohol consumption and mean offspring birthweight was found; however, ADH2*3 did not have a significant impact on mean birthweight for infants born to mothers that drank during pregnancy. These results could be interpreted as possible support for the hypothesis that ADH2 genotype in the infant may impact risk for alcohol-related IUGR. However, this study has limitations in that it is a "nested study of convenience" and involves a relatively small number of infants born to mothers reporting moderate to heavy alcohol use during pregnancy.