RH AND ABO INCOMPATIBILITY, PATHOPHYSIOLOGY, MANAGEMENT

1. RH AND ABO
INCOMPATIBILITY
KANCHAN MEHRA
M.SC NURSING 2ND YAER

2. INTRODUCTION
NOMENCLATURE
Landsteiner and Weiner in the year 1940, discovered specific
unknown antigen in the human red cells. As it was also present in the
Rhesus monkeys, the antigen was named Rh. The individual having the
antigen is called Rh-positive and in whom it is not present, is called Rh-
negative.

3. DEFINITION
Rh disease is the hemolytic disease caused by the incompatibility of
Rh factor in maternal and fetal blood. It occur when the women is Rh
negative and the fetus is Rh positive. If the parents are Rh negative,
there is no hemolytic incompatibility with the infant and the infant is
Rh negative.
-NIMA BHASKAR

4. INCIDENCE
 5–10% (South India – 5%, North India – 10%) in hospital
statistics.
 European and American whites, is about 15–17%; it is very
much insignificant in China (1%) and almost nil in Japan.
 Overall a Rh-negative woman having the chance of Rh-positive
fetus is 60%, irrespective of the father’s genotype.

5. GENOTYPE
 The complete genetic make up of the Rh blood group of an
individual is its genotype.
 Because of lack of proper antisera against anti-e, anti-c and anti-k
the D antigen is the most potent and accounts for almost all
damages (95%).
 An individual carrying D on both sets of antigens (DD) is called
homozygous and when carrying D only (Dd) in one set, it is called
heterozygous

6. RED CELL ALLOIMMUNIZATION
Alloimmunization (isoimmunization) is defined as a
production of immune antibodies in an individual in
response to foreign red cell antigen derived from another
individual of the same species.
 It occurs in two stages:
(1) sensitization and
(2) immunization.

7. METHODS:
1) Transfusion of mismatched blood:
 In ABO group incompatibility, there are naturally
occurring anti-A and anti-B isoagglutinins, which result in
immediate adverse reaction.

8.  In case of Rh group, there is no such naturally occurring
antibody and as such there is no immediate reaction.
 The women may suffer a severe hemolytic reaction to the
subsequent mismatched transfusion.

9. As a result of pregnancy (Rh-negative woman bearing a Rh-
positive fetus):
 Normally, the fetal red cells containing the Rh antigen rarely
enter the maternal circulation.
 The following are the conditions where the risk chance of
fetomaternal bleed is present: miscarriage ,MTP, genetic
amniocentesis, embryoreduction, ectopic pregnancy
,hydatidiform mole ,CVS, cordocentesis ,placenta previa with
bleeding ,placental abruption ,IUFD ,external cephalic version ,
abdominal trauma and the delivery of a Rh-D positive infant to a
Rh negative mother.

10.  This is much more (15–50%) likely to occur during third
stage of labor and following cesarean section or manual
removal of placenta.

11. ABO INCOMPATIBILITY
Incompatibility for the major blood group antigens A and B,and it is
the most common cause of hemolytic disease in newborn infants.
Approximately 20 percent of newborns have ABO blood
group incompatibility, however, only 5 percent are clinically
affected, and the resulting anemia is usually mild.

12. This condition is
differs from Rh
incompatibility
ABO incompatibility is often
seen in firstborn infants
most group O women have
developed anti-A and anti-B
isoagglutinins before pregnancy
from exposure to bacteria
Second, ABO alloimmunization can affect
future pregnancies
Last, most anti-A and anti-B antibodies are
immunoglobulin M (IgM), which do not cross the
placenta.

13.  ABO incompatibility has a protective effect against the
development of Rh sensitization. This protective effect is
significant when the mother is type O and the father is type
A, B or AB.
 The reasons are-
ABO incompatible fetal cells
are cleared from the maternal
circulation rapidly before
they are trapped by the
spleen.
Maternal anti-A or anti-B
antibodies damage the Rh-
antigen so that it is no longer
immunogenic.

14. MECHANISM OF ANTIBODY FORMATION
IN THE MOTHER
If the ABO compatible (mother and fetus have the same
ABO group or when the fetus is group “O”), Rh-positive
fetal red cells enter the mother’s blood, they remain in the
circulation for their remaining lifespan.
Thereafter, they are removed from the circulation by the
reticulo-endothelial tissues

15. The antibody production is related not only to the
responsiveness of the reticuloendothelial system but also to
the amount of Rh antigen, therefore to the number of red cells
that have entered the maternal blood.
Because this takes a long time, immunization in a first
pregnancy is unlikely. Detectable antibodies usually develop
after 6 months following larger volume of fetomaternal bleed.
But, if the fetomaternal bleed is less than 0.1 mL, the
antibody may not be detected until boosted

16. TYPES OF ANTIBODIES
Two types of antibodies are formed :
 IgM—This type of antibody is the first to appear in the maternal
circulation and agglutinates red cells containing D when
suspended in saline. IgM being larger molecules cannot pass
through the placental barrier and is not harmful to the fetus.

17.  IgG- It is also called incomplete or blocking antibody. It will
agglutinate the red cells containing D only when suspended in
20% albumin, it can cross the placental barrier and cause
damage to the fetus. It appears at a later period than, does the
IgM antibody.

18. FETAL AFFECTION BY THE Rh ANTIBODY
fetus Mother
Rh-negative
fetus
The antibody formed in the maternal system (IgG) crosses the
placental barrier and enters into the fetal circulation. The
antibody will not have any effect on Rh-negative fetus
Rh-positive
fetus
The antibody becomes attached to the antigen sites on the
surface of the fetal erythrocytes.
The affected cells are rapidly removed from the circulation by
the reticulo-endothelial system

19. ANTENATAL INVESTIGATION OF Rh-
NEGATIVE MOTHERS
 Investigation of blood for Rh and ABO grouping
 If the woman is found Rh-negative, Rh grouping of the
husband is to be done
 If the husband is also Rh-negative, i.e. compatible mating,
there is no problem so far as Rh factor is concerned.
 But if the husband is found to be Rh-positive, further
investigations are to be carried out

20.  OBSTETRIC HISTORY:
(a) If the woman is a primigravida with no previous history
of blood transfusion, it is quite unlikely that the baby will
be affected.
(b) In a parous woman, a detailed obstetric history has to be
taken. History of prophylactic administration of anti-D
immunoglobulin following abortion or delivery should be
enquired

21.  ANTIBODY DETECTION:
- IgG antibody is detected by indirect Coombs’ test.
- If the test is found negative at 12th week, it is to be
repeated at 28th and 36th week in primigravida. In
multigravida, the test is to be repeated at monthly intervals
upto 24 weeks and at every 2 weeks thereafter.
- If the test is found positive : The patient should be
supervised to tackle with Rh problem

22.  AUTOMATED MEASUREMENT OF ANTIBODY
(Specific anti-D) is a more accurate test. The safe level of
antibody in the maternal serum is < 4 IU/mL.
-Anti-D level > 4 IU/mL but <15 IU/mL has moderate risk
for hemolytic disease of the fetus and newborn(HDFN)
-Anti-D level >15 IU/mL can cause severe HDFN.
- DOPPLER ULTRASOUND

23. PREVENTION OF Rh-IMMUNIZATION
-To prevent active immunization
- To prevent or minimize fetomaternal bleed
-To avoid mismatched transfusion

24.  TO PREVENT ACTIVE IMMUNIZATION:
-Rh anti-D immunoglobulin (IgG) is administered
intramuscularly to the mother following childbirth.
-It should be administered within 72 hours or preferably earlier
following delivery or abortion.

25.  DOSE:
-Anti D-gammaglobulin is administered intramuscularly to the
mother 300 µg following delivery.
-All Rh-negative unsensitized women should receive 50 µg of Rh-
immune globulin IM within 72 hours of induced or spontaneous
abortion, ectopic or molar pregnancy or CVS in the first
trimester.
-Women with pregnancy beyond 12 weeks should have full dose
of 300 µg.

26.  DURING PREGNANCY:
-If the woman is Rh negative and has no antibody, she should
have one dose of 300 µg Rh immune globulin as
prophylaxis at around 28 weeks (ACOG–1999) and again
after birth (within 72 hours).

27. TO PREVENT OR MINIMIZE FETOMATERNAL BLEED
Precautions during cesarean section:
 To prevent blood spilling into the peritoneal cavity.
 Manual removal of placenta should not be done as a
routine.
— Prophylactic ergometrine with the delivery of the anterior
shoulder
— Amniocentesis should be done after sonographic
localization of the placenta to prevent its injury.

28. - Forcible attempt to perform external version under
anesthesia should be avoided.
- Manual removal of placenta should be done gently.

29. PLAN OF DELIVERY AND MANAGEMENT
 UNIMMUNIZED MOTHERS: In cases where there is no
detectable antibody found during pregnancy, an expectant
attitude is followed till term. Tendency of pregnancy to overrun
the expected date should not be allowed.
 IMMUNIZED MOTHERS: As mentioned previously, whenever
there is evidence of hemolytic process in the fetus in utero, the
patient should be shifted to an equipped center specialized to
deal with Rh problems. An intensive neonatal care unit,
arrangements for exchange transfusion and an expert
neonatologist are the basic requirements to tackle the affected
babies.

30.  Methods of delivery:
(1) Amniotomy (low rupture of the membranes), Vaginal
prostaglandin gel (PGE2) could be used to make the cervix
ripe.
(2) Cesarean section: In cases when termination has to be
done prematurely (say 34–37 weeks)

31. CARE DURING DELIVERY
 Vaginal delivery:
-Careful fetal monitoring is to be done to detect at the
earliest, evidences of distress
-Prophylactic ergometrine during second stage should be
withheld
-Gentle handling of the uterus in the third stage and
-To take care of postpartum hemorrhage.

32.  Cesarean section:
-To avoid spillage of blood into the peritoneal cavity and routine
manual removal of placenta should be withheld.
-Clamping the umbilical cord: In either methods, the cord is to be
clamped as quickly as possible to minimize even minute
amount of antibody to cross to the fetus from the mother. The
cord should be kept long (15–20 cm) for exchange transfusion,
if required.

33. OTHER TREATMENT
 Plasmapheresis has been tried to remove several liters of
maternal plasma with maternal anti-D antibodies. IVIG is
then given. Due to its lack of definite benefit, it is not
commonly done.
 A dose of 1,000 mg/kg IVIG weekly has been used.
 Delivery at around 34–36 weeks leads to neonatal survival
to about 100% with low long-term morbidity

34. PROGNOSIS
Prognosis of the baby depends on:
(1) Genotype of the father
(2) Genotype of the fetus
(3) Maternal antibody level
(4) History of previous affection of the baby due to
hemolytic disease and
(5) Availability of sophisticated diagnostic and
therapeutic facilities for the affected babies (specialist
fetal medicine care unit).

35.  However, with use of intensive management protocols such as
repeated fetal Doppler study, amniocentesis, cordocentesis,
intrauterine fetal transfusions (when necessary) the neonatal
survival is 100%.
 An immunized mother who has anti-D level more than 400
IU/L, should be advised for anti-D donation.
 BREASTFEEDING: There is no contraindication of
breastfeeding in immunized mothers, although trace amount of
antibodies are excreted through the breast milk.

36. SUMMARY
At the end of the Presentation Rh and Abo incompatility can be helpful
for students to know the problem of Rh and Abo incompatility, and ,
understand the feature, mechanism of antibody formation, diagnosis,
treatment, prevention, and prognosis of Rh and Abo incompatility.

37. ABSTRACT
B.V.Sai Prasad, Md Khader Faheem, N.V.H.Rajesh Krishna, et al, conducted
study on Distribution and Prevalence of ABO and Rhesus Blood Groups in
Blood Donors in Care Centre in Southern Region of Andhra Pradesh.A
retrospective study was carried with 43839 blood donors’ records.The blood
group was determined by forward grouping (cell grouping) and reverse (serum
grouping) grouping methods. Gene / allelic frequencies of the variables were
calculated. Total number of blood units collected was 43839;from January
2012 to December 2017.The study showed there were 93.37% of male donors
and 6.62% of female donors. There were 95.96% of Rh positive and only
4.03% of Rh negative blood units. Thus the study concluded that the most
common blood group -‘O’ Positive (44.53%) and the least common was ‘AB’
Negative (0.51%).

38. BIBLIOGRAPHY:-
 Dutta D.C. Textbook of Obstertics , 8th Edition. India. Jaypee Bothers Medical
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 F. Cunningham, Kenneth Leveno, Steven Bloom, Catherine Y. Spong, Jodi Dashe,
Williams Obstetrics 24th edition (2014, McGraw-Hill Professional), Pp- 306- 313
 Prasad B.V.Sai, Faheem Md Khader, Krishna N.V.H.Rajesh, Distribution and
Prevalence of ABO and Rhesus Blood Groups in Blood Donors in Care Centre in
Southern Region of Andhra Pradesh ,IOSR Journal of Dental and Medical Sciences
(IOSR-JDMS) [cited on – 12 Nov 2019]e-ISSN: 2279-0853,.Volume 17, Issue 7 Ver.
3(July. 2018), PP 01-05 ,available at -www.iosrjournals.org