Skeletal development in fetuses of rats consuming alcohol during gestation

Sprague-Dawley female rats were fed either 20% ethanol in drinking water and rat chow ad libitum (alcohol group) or were pair-fed to the alcohol group, with starch substituted isocalorically for ethanol (pair-fed group) or were fed rat chow and tap water ad libitum. After 4 weeks they were bred and the alcohol group was changed to 30% ethanol in water. On day 20 of gestation the fetuses were removed and stained with Alcian Blue and Alizarin Red S. The skeletons were examined for the appearance of ossification centers and the ossification centers in the fore- and hindlimbs were measured. Fetuses from the alcohol group weighed significantly less than those of the two control groups. Ossification centers expected to appear in the skull on day 20 were absent in most of the alcohol group fetuses, but present in the control fetuses. There were fewer ossification centers in the sternum and in the limbs, and the ossification of vertebral centra has progressed less (both anteriorly and posteriorly) in the alcohol fetuses than in the controls. Dimensions of the ossification centers in the limbs were less in the alcohol fetuses than in the controls. No gross malformations were seen in any of the fetuses. It is concluded that by day 20 of gestation skeletal development is retarded by approximately one day in the fetuses of rats given alcohol prior to and throughout gestation.