A Single Dose of Ethanol Suppresses Rat Embryo Development in Vivo

In humans and animal models, maternal ethanol consumption during pregnancy results in a variety of fetal defects collectively termed the fetal alcohol syndrome (FAS). Limited follow-up studies suggest that FAS children fail to achieve normal physical or mental development despite significant postnatal intervention. Although the complete FAS appears to result only when chronic, excessive alcohol consumption occurs throughout pregnancy, several investigators have suggested that ethanol consumption at intermediate levels may induce components of FAS. The defect most consistently observed in neonates exposed to ethanol is growth retardation. Even those children whose mothers consume limited amounts of ethanol during pregnancy have a significant incidence of fetal growth deficiency. We now report that a single dose of ethanol administered to female Holtzman rats within 8 hr after mating results in a dose-dependent retardation of cell division in the fertilized ova. The growth retardation is sustained up to 42 hr after the dose and the embryos of young mothers are especially sensitive to ethanol. Animals with high blood alcohol levels (<150 mg/100 ml) show a significant increase in abnormal embryo morphology. These data suggest that maternal consumption of a single dose of ethanol near the time of conception retards embryonic growth and may be detrimental to the developing organism. Further, young female rats receiving a high dose of ethanol had significantly lower uterine weights and a lower number of corpora lutea per ovary, suggesting that a single dose of ethanol has a detrimental effect on maternal reproductive ability.