Rh incompatibility, cause, manifestations

1. Rh- incompatibility
Anjana Thomas

2.  The Rhesus factor gets its name from
experiments conducted in 1937 by scientists
Karl Landsteiner and Alexander S Weiner.
 Their experiments involved rabbits which, when
injected with the Rhesus monkey’s red blood
cells, produced an antigen that is present in the
red blood cells of many humans.

4.  Rh incompatibility is a condition which
develops when there is a difference in Rh
blood type between that of the pregnant
mother(Rh negative) and that of the fetus
(Rh positive)

5.  A person’s Rh type is generally most relevant with
respect to pregnancies
 If the pregnaant women and her husband are Rh
negative, there is no reason to worry about Rh
incompatibility
 If she is Rh negative and her husband is Rh positive,
the baby will inherit the father’s blood type,
creating incompatibility between mother and her
fetus

6.  If some of the fetal blood gets into mother’s
blood stream, her body will produce
antibodies.
 These antibodies could pass back through the
placenta and harm the developing baby’s red
blood cells.

7.  Usually placenta acts as barrier to fetal
blood entering maternal circulation.
However, sometimes during pregnancy or
birth, fetomaternal haemorrhage can occur.
The women’s immune system reacts by
producing anti D antibodies that causes
sensitization.

8.  A difference in blood type between a
pregnant woman and her baby causes Rh
incompatibility. The condition occurs if a
woman is Rh negative and her baby is Rh
positive.

9.  An earlier pregnancy
 An ectopic pregnancy, a miscarriage or an
induced abortion.
 A mismatched blood transfusion or blood and
marrow stem cell transplant.
 An injection or puncture with a needle or
other object containing Rh positive blood

10.  1st pregnancy
Father RhD +
Mother RhD –
Fetus RhD + Fetal – maternal blood
transfer during labour
First newborn
RhD + safe
But mother RhD
– is now
sensitized to
Rhd antigen

11.  Second pregnancy
Rapid
production
of IgG anti
D by
mother
Maternal
IgG anti D
crosses
placenta
IgG anti D
attaches to
fetal BBC &
marks them
for
destruction
Fetal or
newborn
hemolytic
anemia
Increased
billirubin,
CNS
damage(ker
nicterus),d
eath
Repeat
encounter
with
Fetal
RhD
antigen

13.  The klehauer- betke test or flow cytometry
 Indirect coomb test
 The direct coomb test
 Blood count
 Billirubin – direct & indirect

14.  Mildest form
 Hemolysis
 Jaundice
 Total body swelling
 Respiratory distress
 Circulatory collapse
 Kernicterus
 It occur several days after delivery – poor
feeding, decreased activity

15.  Hydrops fetalis
 Icterus gravis neonatrum
 Congenital anemia of newborn

16.  This is a most serious from of Rh haemolytic
disease. Excessive destruction of the fetal
red cells leads to severe anaemia, tissue
anoxaemia and metabolic acidosis.

17.  This clinical entity is the effect of lesser
form of fetal haemolysis. The baby is born
alive without evidence of jaundice but soon
develops it within 24 hours.

18.  Mildest form of diseases where the
haemolysis is going on slowly. Although
anemia develops slowly with in first few
weeks

19.  Rh incompatibility is treated with a medicine
called Rh immunoglobulin. Treatment for the
baby who has hemolytic anemia will vary based
on the severity of the condition
 If Rh incompatibility is diagnosed during
pregnancy, mother will receive Rh
immunoglobulin in seventh month of pregnancy
and again with in 72 hours of delivery.

20.  Mother also may receive Rh immunoglobulin
if the risk of blood transfer between mother
and the baby is high (for example, a
miscarriage, ectopic pregnancy, or bleeding
during pregnancy)

21.  Immunization with Rh immunoglobulin
 Prevent or minimize feto maternal bleed
 Avoid mismatched transfusion
 Amniocentesis should be done after
sonographic localization of placenta