Some
information from NCT website
People
whose blood is rhesus positive have a substance known as D antigen on the
surface of their red blood cells. Rhesus negative people do not. About 15% of
women are rhesus negative. This isn't usually a concern for a first pregnancy,
but it may mean some extra care is needed to avoid problems if you get pregnant
again.
A
rhesus negative woman can be pregnant with a rhesus positive baby if the baby's
father is rhesus positive. If any of the baby’s blood enters the woman’s
bloodstream, the woman’s immune system can develop antibodies (infection-fighting
proteins) against the rhesus antigens. This is known as sensitisation. A
transfer of blood can occur during birth, or if the woman has a bleed or an
injury.
Production
of the antibodies is not a problem in a first pregnancy, but when the woman is
pregnant next time with a rhesus positive baby, her antibodies can attack that
baby’s red blood cells. This can result in a serious condition called
haemolytic disease of the newborn, which leads to anaemia and jaundice in the
baby.
If the woman is given an injection
of a solution called ‘Anti-D’, it will ‘mop up’ any rhesus positive antigens,
preventing production of antibodies against the baby. Anti-D injections reduce
the risk of a rhesus negative woman becoming sensitised.
NICE recommends routine antenatal
administration of Anti-D to all rhesus negative women in case sensitisation
occurs. This can be given as a one-off dose at 28-30 weeks or as two doses at
28 and 34 weeks. It is quite safe for both the mother and the baby.
No comments:
Post a Comment