Thirty-two pregnant Long-Evans rats were divided into 10 groups of 3 or 4 pregnant rats, and each rat was given a single dose of 4 ml
ethanol/kg (20 ml/kg of a 20%
solution) between d 6 and 15 of gestation. An 11th group of 50 pregnant rats received distilled water and served as controls. Offspring
body weights were decreased in groups of rats given
ethanol as compared to controls (3.0-3.6 g, versus 3.9 g for controls). Total litter weight was decreased in dams given
ethanol on d 6. Skeletal variants were seen in 13-78% of the offspring given
ethanol, compared to 0.6% of the controls. Variations may be considered as additional signs of embryotoxicity. Malformations such as
hydronephrosis, pelvic kidney, microcephalus,
cranioschisis, and
microphthalmia occurred in 72-100% of the
ethanol treated offspring, as compared to 12% of controls.
Hydronephrosis was most frequent on d 9 or 14, pelvic kidney on d 8 and 11, and
microphthalmia from d 10-12.
Cranioschisis was maximal on d 7, 11, and 15, and microcephalic offspring were most frequently born to dams given
ethanol on d 7 or 14. Skeletal defects were usually single entities, while soft-tissue anomalies occurred in a consistent pattern. These results suggest that
ethanol is a stage-specific
teratogen in the rat at comparable exposure levels attained by many humans.