Rh D foeto-maternal alloimmunization prophylaxis with anti-D immunoglobulins reviewed in the era of foetal RHD genotyping.

In Belgium, prevention of anti-D immunization is currently based on systematic postnatal prophylaxis associated with targeted antenatal injection in high-risk situations of foeto-maternal haemorrhage.The failures of prevention are mainly due to the non-respect of established guidelines for RhlG prophylaxis, and to spontaneous undetected foetal-maternal haemorrhages without any obvious cause during the third trimester of pregnancy. In order to reduce the rate of residual post-pregnancy anti-D immunization, several countries decided to associate the classical prophylaxis to a routine antenatal anti-D prophylaxis (RAADP) during the 28th or 29th week of gestation. Since a few years, the foetal RHD genotyping in maternal plasma enables us to limit the antenatal prophylaxis only to those D- women carrying a D+ foetus. This paper deals with: the advantages of an antenatal prevention in the light of non-invasive foetal RHD genotyping, the rules rendering prevention protocols efficient whatever the algorithm applied, and the recommended immuno-haematology follow-up of women who received RhlG.