Compensatory embryonic development in the rat following maternal treatment with ethanol.

A pattern of congenital anomalies, termed "fetal alcohol syndrome", has been recognized in the offspring of mothers with chronic alcoholism. The teratogenic mechanism is not known. Moderate doses of ethanol, administered to pregnant rats from day 5 through 8 of gestation, impaired blastocyst development. The mean fetal weight on day 20 of gestation was reducted, compared to that of the controls. However, fetal survival was not affected and congenital anomalies were not detected in any of the offspring. These results indicate that considerable compensatory growth and repair may obscure early embryopathic lesions before development is completed.