This document discusses ABO incompatibility between a mother and fetus/newborn. The main points covered are: - ABO incompatibility can cause hemolytic disease of the newborn (HDN), occurring in about 25% of pregnancies when the mother's blood type is O and the fetus's is A, B, or AB. - The disease is caused by IgG antibodies from the mother's blood crossing the placenta and reacting against antigens on the fetus/newborn's red blood cells. - Diagnosis involves testing the newborn's blood type and bilirubin levels as well as direct Coombs testing of the mother's antibodies. - Management focuses on phototherapy or

1. ABO
INCOMPATIBILITY
By
P.Padma Priyanka

2. CONTENTS
 INTRODUCTION
 BLOOD TYPES
 MODERATING FACTORS
 DIFFERENCE B/N ABO AND RH INCOMPATIBILITY
 HS AND ABO-HDN
 DIAGNOSIS- HISTORY,LABORATORY
 MANAGEMENT
 SUMMARY

3. INTRODUCTION
 ABO-Hemolytic disease of newborn
 25% of pregnancies
 HDN develops only in 1/10 such offsprings
 O group mother and A/B group fetus
 Female>male
 OA>OB
 Cause-reaction of maternal anti-A/B to antigen present
on RBC of fetus or newborn
 IgG antibodies cross the placenta

4. BLOOD TYPES
 ABO system in 1990
 A,B,AB,O
 Central principle is ANTIGENS
 Isoantibodies against isoantigens
 Important for transfusion

5. Co-dominant inheritance of ABO system

6.  ABO on 9q34 -glycosyltransferase
 A- N-acetyl galactosamine
 B- galactose
 H on 19
 H antigen-precursor
 Antigens contained in food,bacteria and vaccines

8. MODERATING FACTORS
 Mild nature and low incidence of ABO-HDN accounts
for
low antigenicity of AB factors
wide distribution
fewer antigen sites on preterm RBC

9. DIFF B/N ABO & RH
INCOMPATIBILTIES
 May occur in first born
 Increasing frequency of disease in subsequent
pregnancies is generally not present
 The subsequent babies may be more effected or less
effected or even spared

10. HS AND ABO-HDN
 Increased osmotic fragility, autohemolysis,
splenomegaly in both
 But autohemolysis is not corrected by glucose as in HS
 Family history,long-term course,MCHC differentiate HS
from ABO-HDN

11. DIAGNOSIS(suspected)
 Antenatally –
 Past history of ABO-HDN in previous sibling
 Titer of anti-A/anti-B in mother is >1:64
 Postnatally –
 Early onset of jaundice <24hrs
 A/B group baby of O mother
 Mild splenomegaly
 Anemia – usually absent

12. DIAGNOSIS(laboratory)
 Serum bilirubin
 Reticulocytosis
 Spherocytosis
 Fragility of RBC
 Confirmation of antibodies-eluted serum
 Direct coomb’s test
 Maternal IgG antibodies in ADCC assay
 Detection of antigen density on RBC
 High titres of anti-A/B hemolysins-in maternal serum

13.  Start intensive phototherapy if bilirubin exceeds
10mg/dl at 12hrs
12mg/dl at 18hrs
14mg/dl at 24hrs
15mg/dl at any time
 Exchange transfusion-if it reaches 20mg/dl
MANAGEMENT

14. Guidelines for phototherapy

15. Guidelines for exchange transfusion

16. SUMMARY
 INCIDENCE
 O group mother and A/B group fetus
 Co-dominant inheritance
 HS and ABO-HDN
 Diagnosis
 Management –phototherapy and exchange transfusion

17. REFERENCES
 Manual of neonatal care-CLOHERTY
 Care of new born-MEHERBAN SINGH
 HARRISON’S principles of internal medicine

18. THANK YOU