The majority of Rh(D) negative immunised mothers have some sahne
agglutinating anti-D in their sera during subsequent pregnancies. This saline
antibody is related to a complex effect on the severity of haemolytic disease of the
foetus: the stillbirth rate is reduced while the severity of disease among liveborn
infants increases slightly with rising titres of saline anti-D. Also, when the observed
sahne anti-D titre is 1 the severity of disease is markedly incresed while the protective
effect of sahne anti-D on the stillbirth rate fails to operate. The significance
of this is discussed.
Mothers of group A and especially group B are more liable to form saline anti-D,
while the severity of HDN increases if the mother is of group B or AB.