Placental blood flow in rats fed alcohol before and during gestation

Female Sprague-Dawley rats were either given 20% alcohol in drinking water and solid diet $\text{ad libitum}$ (alcohol group) or were pair-fed to the alcohol group (pair-fed group) or were given water and solid diet $\text{ad libitum (ad libitum}$ group) for four weeks. They were then mated and the alcohol group was changed to 30% alcohol in water. On day 20 of gestation each rat was injected with ⁵⁷Co-labeled microspheres into the left ventricle and radioactivity was determined in the placentas and kidneys. Cardiac output and blood flow to the placentas and kidneys was calculated. Fetuses and placentas were weighed, and the osmolality of the maternal plasma and water content of the muscle was determined. Cardiac output and blood flow to the kidneys did not differ among the three groups. Blood flow to the placenta, whether expressed as m1/min/g placenta or m1/min/placenta, or as % of cardiac output was significantly reduced in the alcohol group compared with the pair-fed and $\text{ad libitum}$ groups, which did not differ from one another. Fetuses were significantly lighter and placentas were significantly heavier in the alcohol group than in the other two groups. Plasma osmolality was increased and muscle water was decreased about 7% in the alcohol group, indicating a moderate degree of dehydration. It is concluded that chronic alcohol consumption leads to a redistribution of blood, with less blood supplying the placentas. This may contribute to the growth retardation seen in fetal alcohol syndrome.