The purpose of this study was to examine, in the pregnant ewe and its fetus, some of the physiological consequences of acute and chronic ethanol exposure. Ethanol was infused intravenously (2 g/kg/day over 2 h) to pregnant ewes from day 100 of pregnancy to term. Control animals received isocaloric infusions of 5% dextrose. Animals were pair-fed and allowed water ad lib. Maternal (n = 5) systolic, diastolic, and mean blood pressures and heart rate rose significantly by 1 h after starting ethanol, whereas fetal (n = 4) blood pressure and heart rate did not change during ethanol infusion. Maternal ethanol infusion produced a significant rise (p less than 0.01) in both fetal (n = 8) and maternal (n = 10) plasma cortisol levels. Peak blood ethanol concentration was significantly higher in the ewe (240 +/- 6 mg.dl-1, n = 7) than in the fetus (190 +/- 9 mg.dl-1, n = 6) at the end of the 2-hour infusion. Maternal rate of elimination after ethanol infusion was terminated was 40 mg.dl-1 per hour, while fetal elimination was 10 mg.dl-1 per hour. Body weights and crown-rump lengths of fetuses from 0.82 to 1.0 gestation were significantly less in ethanol-treated animals than in age-matched control animals. Fetal plasma thyroxine and triiodothyronine increments following thyrotrophin-releasing hormone administration were significantly less in alcohol-treated than in control animals. Thus, chronic exposure to ethanol during the latter part of gestation impaired fetal growth and altered fetal endocrine function in these animals.