A surprising effect of paternal alcohol treatment on rat fetuses.

Male rats were intubated with either 5, 2.5, or 0 g/kg alcohol. Animals in the latter two groups were pairfed to those in the 5 g/kg group. A fourth group of males was not treated and was fed ad lib. Males were bred once after 3 weeks of intubation and twice after 9 weeks of intubation. Females in the first two breedings were sacrificed prior to delivery, whereas females in the last breeding were allowed to deliver their litters. There were no significant decreases in male fertility or litter size, but fecundity was reduced in females bred to alcohol-treated males when all breedings were pooled. Newborn weights (third breeding) were not significantly affected by paternal alcohol treatment, but fetal weights in the first two breedings were significantly increased in association with paternal alcohol treatment. There was also an alcohol-related increase in the number of male fetuses in breeding one, and an increase in placental weights in breeding two; the placental index (placental weight/fetal weight) was also decreased by paternal alcohol treatment for fetuses in the second breeding. These results suggest paternal alcohol treatment can have effects on offspring body weights, which are not observable once females have given birth.