Glucose turnover was measured in term pregnant rats fed ethanol (30% of caloric intake) throughout gestation. Ethanol ingestion significantly reduced maternal weight gain and term fetal body weight when compared to pair-fed or ad libitum-fed controls. At term the blood glucose level and 6-3H-glucose turnover were reduced when compared to either control group. The rate of gluconeogenic recycling, indicated by the difference between 6-3H and 6-14C-glucose turnover determinations, was reduced by ethanol ingestion to half that of the control groups. Glucose turnover correlated with both conceptus weight and blood glucose level. Impaired maternal glucose homeostasis, including a reduced gluconeogenic response to the metabolic demands of late pregnancy, may thus contribute to the effects of ethanol on intrauterine growth.