Colloid osmotic pressure in erythroblastosis fetalis.

Measurements were made of total proteins, albumin, and colloid osmotic pressure on cord blood samples from 15 infants with erythroblastosis fetalis (six of whom were hydropic) and from 151 non-rhesus non-hydropic control infants. The erythroblastotic infants had levels of total protein and albumin which fell within the normal range for gestational age, but their colloid osmotic pressures were abnormally low. It seems that low colloid osmotic pressure may provide a reasonable explanation for the occurrence of hydrops fetalis.