Rhesus Negative Mother
Approximately 85% of the Australian population have a Rhesus (Rh-D) positive blood group and 15% a (Rh-D) negative group. When a Rh-D negative patient becomes pregnant by a Rh-D positive partner there is a 50% or 100% chance that the baby will be Rh-D positive. If the baby’s Rh-D positive blood cells pass into the mother’s bloodstream, as may occur at amniocentesis or CVS then the mother may produce antibodies against these cells. These antibodies may then cross the placenta, bind to and destroy the baby’s own blood cells thus causing anaemia (Rhesus disease).
If the mother is given an injection of Anti-D within 72 hours of the procedure (amniocentesis or CVS) then the baby’s cells which have entered the bloodstream may be neutralised and thus harmful antibodies will not be produced. The baby will therefore be protected from developing anaemia.
It is routine practice therefore to offer all Rh-D negative mothers Anti-D after amniocentesis and CVS.
If you are undergoing invasive testing (amniocentesis or CVS) we must know your blood group. Please ask your referring doctor to provide your blood group in writing. Anti D is given by injection usually into the buttock or arm after invasive testing.