Five families with cases of erythroblastosis foetalis have been studied for the ABO, Rh, MN, and Kell-Cellano blood group systems. In all of them, the father and mother were found to be compatibly mated, and so were the children with their mother, in all systems, except Rh.
Most children were of CDe/cde type, and all mothers cde/cde. The influence of other systems (MN and Kell-Cellano) on Rh incompatibility remains to be investigated. They might play a role in counteracting the effect of Rh incompatibility.
The antibody titre in the mother's blood has clearly appeared to decline gradually, with an increasing time gap between successive pregnancies.
Whether the possibility of having a normal full term pregnancy, resulting in the birth of a healthy child, increases, if the time gap between two successive pregnancies is larger, remains to be investigated.