Maternal ingestion of alcohol is believed to be one factor that greatly influences the development of intrauterine growth retardation (IUGR) and postnatal growth failure. The present study was undertaken to determine whether maternally ingested alcohol adversely affects fetal growth and intestinal mucosal function. Five time-mated New Zealand white rabbit does were given ethanol intravenously (ETH group) (30% vol/vol; 1.0 g/kg/d) on gestational days (GD) 15 through 29 (term, 31 days). Two other rabbits received the same dose of ethanol. Maternal, fetal, and amniotic fluid alcohol levels were measured on GD 24. Four control rabbits (SH group) received normal saline (25 mL, intravenously). At term, the animals were delivered by cesarean section and killed. Seventeen of the 42 ETH fetuses survived the study period (43%); all 24 SH fetuses survived. On GD 24, within 60 minutes after maternal ethanol infusion, the fetal blood alcohol concentration (BAC) increased to 153 +/- 1.97 mg/dL (v maternal, 179 +/- 1.75 mg/dL); the amniotic ethanol level increased to 46 +/- 1.32 mg/dL. Birth weight was lower in the ETH group (46.88 +/- 2.21 g) than in the SH group (55.78 +/- 1.80 g) (P < .01). Disaccharidase activity, an indicator of intestinal mucosal function, showed that lactase activity (per milligram of protein) was significantly lower in ETH fetuses (2.60 x 10(-2) +/- 0.22 UE/mg) than in SH fetuses (3.50 x 10(-2) +/- 0.25 UE/mg) (P = .01); maltase activity and protein content were not affected significantly. This report provides the first description of the adverse effects of maternal alcohol ingestion on the small intestinal mucosal function of the fetal rabbit.