Q: How is the mother (in this case me), affected by mistakenly receiving Rh-antibodies after delivery? I was given antibodies by injection as I was told that my blood group is B negative. However, in a subsequent pregnancy it was revealed that my blood group is A positive and I do not need the Rh-antibodies. I realised there had been a mix up with my lab results some years ago when I was given false information about my blood group.

A:Women who are Rh-negative can form Rh-antibodies when carrying a Rh-positive baby (called isoimmunisation). These antibodies can then cross the placenta to destroy the baby’s Rh-positive red cells resulting in anaemia, and sometimes even death (haemolytic disease of the newborn) of a Rh-positive baby in a subsequent pregnancy. To prevent the formation of Rh-antibodies in such pregnant women, an injection of anti-D is given. Such an injection will have no apparent effect if mistakenly given to Rh-positive women. Even though it will destroy some red cells (haemolysis), the effect is transient as the dose is small.