[Changes in feto-maternal incompatibility and the indications for exchange transfusion]

Since anti-Rho (D) was reputed as the major cause of significant haemolytic disease of the newborn (HDNB), the introduction of Rh-immunoglobulin (Rh-Ig) in the late 1960's made it possible to prevent the risk of sensitisation to Rho (D) in 85-90% of the cases. The use of Rh-Ig has no effect on ABO or non-ABO, non-D incompatibilities. These facts have induced a change in the frequency of HDNB. On the other hand, the use of Rh-Ig has provided evidence that treatment with exchange transfusion has strikingly decreased in HDNB. In order to assess the incidence of potential and actual ABO, Rho (D) and non-ABO, non-D foeto-maternal incompatibility, cord-blood samples from 12,830 newborns were studied. Although potential ABO incompatibility with their mothers was found in 2,470 babies (19.1%), only 183 of them (7.4%) developed actual sensitization. Such figure represents only 1.4% of the ABO incompatibility, as a whole, in all the newborns. Regarding Rho (D), foeto-maternal incompatibility was present in 1,168 babies (9.1%), of whom 39 (3.3%), i.e., 0.3% of all the newborns, developed actual sensitization. Assuming that before the introduction of Rh-Ig 17% of the pregnant women at risk developed anti-D, we had prevented 80.3% immunization. Most of the 39 sensitized women presented circumstances to explain this fact. Only 7 cases of non-ABO, non-D immunization have been found, which represent 0.05% of all the newborns studied. The prognosis of the different forms of foeto-maternal incompatibility is in our hands similar to that published elsewhere.(ABSTRACT TRUNCATED AT 250 WORDS)