Measurement of Placental Blood Flow in the Pig and Its Relation to Placental and Fetal Weight

Abstract
In 12 pregnant sows (Sus scrofa domestica), containing 144 live fetuses, placental blood flow was measured by the indicator fractionation technique using radioactive microspheres. In 8 of these litters, which contained 96 live fetuses, placental blood flow was obtained in absolute units. Significant positive correlations were observed between placental blood flow and placental weight, between placental blood flow and fetal weight, and between placental weight and fetal weight. It is clear that the runt, by comparison with his littermates, has a low birthweight in association with a small placenta and a low placental blood flow.