The inefficient transfer of maternally fed alcohol to nursing rats.

The growth of rat pups nursed by ethanol-drinking mothers or pups exposed daily to ethanol/vapor was monitored for the first three weeks of life. Pups nursed by mothers fed either a 6% ethanol containing liquid diet or a 10% ethanol/water mixture had significantly lower body weights after the 2nd postnatal week than controls. This decrease in pup growth occurred despite pup blood alcohol levels that did not exceed 20 mg%. Only a small fraction of the alcohol fed to mothers ever reached suckling animals. In contrast, pups exposed daily to ethanol vapor regularly achieved blood alcohol concentrations in excess of 250 mg%, but experienced only minimal growth retardation. These results suggest that maternal alcohol feeding cannot be used to study the effects of ethanol upon postnatal development.