Blood groups and Haemolytic Disease of the Fetus and Newborn (HDFN) in pregnancy
If a woman is RhD negative and carrying an RhD positive baby, this can lead to the mother developing red cell antibodies (anti-D) against the baby’s red cells, that may then damage the red cells of baby’s in future pregnancies.
This can lead to anaemia, jaundice and in very severe cases brain injury and death.
This can be prevented by administering an injection called RhD Immunoglobulin (RhD Ig) if you are RhD negative.
To know whether you might need RhD Ig, your clinical care provider will request a blood test called a blood group and antibody screen at your first appointment.
This mother has
RhD negative red cells
and her baby has
RhD positive red cells
Some of the baby’s RhD positive red cells will cross the placenta into the mother’s circulation.
The mother’s immune system detects foreign cells and can develop antibodies to remove them.
In subsequent pregnancies, the antibodies the mother created can cross the placenta and damage and destory the baby’s RhD positive red cells, causing HDFN.
RhD Ig Prophylaxis
RhD Ig prevents an RhD negative mother’s immune system from forming antibodies against an RhD positive fetus.
This prevents the mother from developing anti-D antibodies and HDFN