1. Immune conflict at pregnancy
Andrii Berbets, assist.prof

2. Isoimmunization
• Isoimmunization can involve many of the several hundred
blood group systems.
• This disorder is frequently referred to as Rh
isoimmunization, because the Rhesus (Rh) system is most
frequently involved. For the sake of this discussion, the
Rh system will be used as an example, although it should
be remembered that isoimmunization can and does
develop with many other blood systems such as Kell,
Duffy, Kidd, and others.

3. Red blood cells

4. • Within the Rh system, there are several
specific antigens (C,D,E), the one most
commonly associated with hemolytic disease
being the D antigen.

5. Inheritance of Rh-factor

7. Membrane of RBC

9. • Rhesus (Rh) isoimmunization is an
immunologic disorder that occurs in a
pregnant, Rh-negative patient carrying an Rh-
positive fetus. The immunologic system in the
mother is stimulated to produce antibodies to
the Rh antigen, which then cross the placenta
and destroy red blood cells.

10. Risk of Rh Sensitization
• mismatched blood transfusion (90-95 %)
• full-term delivery
• ABO-compatible or incompatible (14-17 %)
• induced abortion ( 5-6 %)
• Spontaneous abortion (3-4 %)
• amniocentesis (1-3 %)
• full-term pregnancy (1-2 %)
• ectopic pregnancy (< 1 %).

12. Formation of the antibodies

13. Pathophysiology
• The “Rh disease ” results from the Rh negative mother becoming
isoimmunized to an Rh antibody from the red cells of her first child.
• The first Rh positive pregnancy is almost never affected unless the
mother has had a previous blood transfusion with Rh positive blood;
• Once immunized, the mother’s immune system responds by
manufacturing anti Rh isoantibodies with a second pregnancy;
• If the second pregnancy is one in which the fetus is Rh positive, the
mother’s anti Rh Isoantibodies are transferred to the fetus across the
placenta.

14. Pathogenesis
• If the mother produces immunoglobulin M
(IgM)-type antibodies, the molecules do not
cross the placenta, because they are too large.
In the case of Rh factor, however, the maternal
antibody is predominantly the smaller IgG-
type, which can freely cross the placenta and
enter the fetal circulation.

16. Pathogenesis
• The antibody attaches to the Rh+ red blood cells and
hemolyzes them. The bilirubin produced in this hemolytic
process is transferred back across the placenta to the
mother and metabolized. The condition of the fetus is
determined by the amount of maternal antibody
transferred across the placenta and the ability of the
fetus to replace the red blood cells that have been
destroyed.

17. Syndromes
• Anaemia
• Jaundice
• Hydropsy

18. Hydrops fetalis

19. DIAGNOSIS
History.
Laboratory evaluation include such methods of diagnostics as:
Maternal blood is tested for presence of a variety antibodies – “antibody
screening test”, “indirect” and “direct Coomb’s tests”.
• Mild isoimmunization – antibody titer below 1:16. Rarely produce fetal
hydrops and usually do not require any intervention in the pregnancy. The
newborn may be anemic and develop hyperbilirubinemia.
• Severe isoimmunization - titer of over 1:16 or greater is generally
considered the critical point at which there is sufficient risk of fetal
jeopardy to warrant additional evaluation. This should be done
amniocentesis or percutaneous umbilical blood sampling (PUBS).
• Determination of the father's Rh status is extremely helpful.
• Amniocentesis denotes the amount of blood destruction by estimating the
amount of bilirubin pigments in the amniotic fluid;

20. Ultrasonographic investigation

21. Doppler scan

22. Indications to amniocentesis are:
• 1) Antenatal fetal death and isoimminization in previous
pregnancies;
• 2) Hemolytic infant disease in the previous pregnancies;
• 3) Increasing of antibodies titer to 1: 32.
Contraindications to amniocentesis are:
• Threatened abortus and preterm labor;
• Fever;
• Abnormal uterine development.

23. • Amniotic fluid spectrophotometry – there is
an excellent correlation between the amount
of biliary pigment in the amniotic fluid and the
fetal hematocrit beginning at 27 weeks’
gestation.
• Liley chart can be used – it is a
spectrophotometric graph based on the
correlation of cord blood hemoglobin
concentrations at birth and the amniotic fluid
change in optical density at 450m.

24. • Amniotic fluid assessment is of great value in
managing the isoimmunized patient.
• The level of bilirubin in the amniotic fluid
accurately reflects the condition of the fetus.
The level of bilirubin in the amniotic fluid is
determined using a spectrophotometer.
• Normal amniotic fluid subjected to
spectrophotometric analysis has a
characteristic curve, based on optical density
(OD). The presence of bilirubin causes a
characteristic deviation in this curve, at 450
nm.

25. Spectrophotometry of the amniotic
fluid

26. Optical density of the amniotic fluid
Optical density (green Concentration of Risk of hemolytic
light with the wave 450 bilirubin in amniotic disease of fetus
nm) fluid, mg/l
0,15-0,20 0-2,8 Low
0,21-0,34 2,9-4,6 Moderate
0,35-0,70 4,7-9,5 High
More 0,70 More 9,5 Very high

27. Cordocentesis
• Percutaneous umbilical blood
sampling (PUBS) under ultrasound
guidance – fetal blood can be taken
for hematocrit, hemoglobin, blood
gases, pH, bilirubin levels

28. Cordocentesis

29. In specializing obstetrics department:
Plasmapheresis should be started
from early terms of pregnancy
gestation under controll antibodies
titer every two weeks. The course of
treatment include 4-5 times of
plasmopheresis with interval 1-2 days.
Such method of treatment eliminates
circulating immune complexes, and
antibodies.

30. Kernicterus - brain damage caused by
bilirubin
• Most biliribin is bound to albumin in the newborn’s blood. When the
concentration of bilirubin in the newborn blood exceeds in-term
fetus – 307,8 – 342 mkmoll/L, in pre-term fetus – 153-205 mkmoll/L,
the albumin binding sites are all filled, and bilirubin molecules are then
freed to enter the tissues.
• Biliribin is a cytological poison, nad it is a preferentially taken up by
the cells of the basal ganglia. When a sufficient number of basal
ganglia neurons are damaged by the larger amount bilirubin, the
function of the basal ganglia is destroyed.
• The clinical picture is one of motor handicap (similar to cerebral
palsy).

31. Direct fetal intravascular transfusion

32. Pregnant women undergo cesarean section in such
cases as:
– Severe form of hemolytic infant disease in the
term 34-35 weeks after previous antenatal
prevention of fetal hyaline membranes syndrome;
– Hydrops fetalis in any gestation term because of
interm pregnancy would provoke antenatal fetal
death.

33. Stages of hemolytic disease of infant
severity
I stage II stage III stage
Clinical symptom
Anemia, hemoglobin 150 150-100 100
level in umbilical cord
(g/L)
Jaundice, bilirubin level 85,5 85,6-136,8 136,9
in umbilical cord
(mkmol/L)
Edema Subcutaneous Edema of Hydrops
edema subcutaneous fetalis
fat and ascites

36. Indications to exchange blood
transfusion in infants
In -term fetus : Pre-term fetus
Laboratory symptom
1 day Repeated 5 day 1 day Repeate 5 day
d
Indirect bilirubin, > 68,42 300,7 59,9 273,6
mkmoll/L
Indirect bilirubin per 6,8 6,8 5,1 5,1
hour, mkmoll/L
Hemoglobin, g/L < 150 < 150
Hematocrit <0,4 < 0,4

39. Prevention
• administration RhoGAM (Rh immune globulin) soon
after delivery could, by passive immunization,
prevent an active antibody response by the mother
in most cases.
• Rh immune globulin is effective for only the D
antigen of the Rh system. No similar preparations
are available for patients sensitized with the many
other possible antigens.
• It is now standard practice for Rh- patients who
deliver Rh+ infants to receive an intramuscular dose
of 300 mkg of Rh immune globulin (i.e., RhoGAM)
within 72 hours of delivery.

40. Prevention

41. Indications of RhoGAM administration in a n Unsesitized Rh-negative
patient (unless the father of the infant is known to be Rh-):
• at approximately 28 weeks’ pregnancy – reduce the risk of
sensitization to 0.2 %;
• within 3 days ( 72 hours of delivery) days of delivery of an Rh-positive
infant – the risk of subsequent sensitization decreases from
approximately 15 % to 2 %;
• at the time of amniocentesis;
• after positive Kleihauer-Betke test - allows the identification of fetal
cells in maternal circulation in cases of trauma or bleeding during
pregnancy to which fetomaternal hemorrhage has occurred.;
• after ectopic pregnancy, spontaneous or induced abortion – 50 mg of
RhoGAM can be used to prevent sensitization.

42. NONRHESUS BLOOD GROUP
ISOIMMUNIZATION
• ABO hemolytic disease and non-Rh D/non-ABO hemolytic disease are
rela-tively more common.
• ABO hemolytic disease is associated with milder fetal kernicterus and, rarely,
hydrops, probably because of the relatively smaller number of A and В
antigenic sites on fetal red blood cells and because anti-A and -B are IgM and
thus do not traverse the placenta well; that which does cross has a high
propensity for other binding sites besides fetal red blood cells. This disease
usually occurs in the first pregnancy, and amniocentesis and early delivery are
rarely indicated.
• Non-Rh D/non-ABO hemolytic diseaseis frequently associated with blood
transfu-sion, because "compatible" blood transfu-sion is matched only to the
ABO and Dd antigens. Pregnant women who are affected by the common and
uncommon antibodies that can cause hemolytic disease of the new- born are
managed in the same way as those who are Rh-. Those women with
antibodies that are very rarely or unassociated with hemolytic disease of the
newborn need not be treated.

43. Thank you!