The document discusses ABO blood group incompatibility between mother and baby. It explains that mothers with blood group O naturally have anti-A and anti-B antibodies that are mainly IgM and do not cross the placenta. However, if the baby's blood group is A or B, the mother will produce IgG antibodies upon exposure to the baby's red blood cells, and these antibodies can cross the placenta and cause mild hemolysis in less than 1% of incompatible babies. The jaundice is usually mild and appears within 24 hours of birth. Positive Coombs test occurs in only 3-4% of cases. Exchange transfusions are extremely rare for ABO incompatibility.

1. Dr: Sheikh Aasif Rasool
 Department : paediatrics
 TMMC&H
Topic : ABO incompatibility

12. PRINCIPLE:-
The mother with blood group o has got
naturally occurring Anti-A and Anti-B
agglutinins. These antibodies are mainly IgM
and do not cross the placenta. If the fetus
happens to be blood group A or B
corresponding to that of father the immune
antibodies are formed in response to the
entry of A or B antigen bearing fetal RBC, into
the maternal circulation, as these are mainly
IgG..

13. They can cross the placenta into the fetal
circulation and cause variable amount of
hemolysis due to antigen –antibody reaction
. Although 15% of babies have got ABO
incompatibility only in less than 1%
hemolysis occurs.

14.  The jaundice is usually mild appearing
within 24hrs.The affection is less as
because the antibodies have got other
tissue binding sites apart from fetal RBC.
The diagnosis is made only after birth.
Positive direct coomb”s test occurs in only
3 to 4% cases. Microspherocytes on blood
smear are usually characteristic.Reticulocyte
count is usually increased.

16.  Need of exchange transfusion is extremely rare

24.  DC Dutta’s text book of gynae & obs .
 Essence of pediatrics by prof. Dr MR khan.