When the mother blood group is Rh (-) negative and the father
is Rh (+) positive, it is called Rh incompatibility (blood incompatibility). In
these pairs, the baby can be Rh (+) or Rh (-). If baby Rh (-) is not a problem,
but if baby Rh (+), blood incompatibility can lead to Rh immunization
(interaction) and some problems. Rh incompatibility, that is, blood
incompatibility and rh immunization are different things, they should not be
confused. Rh immunization, that is, interaction does not occur in every
pregnancy with blood incompatibility.
There is no blood incompatibility in any case except that the
mother blood group is Rh negative and the father is Rh positive.
In the presence of Rh incompatibility, if the baby is
positive, mother's blood and baby's blood come into contact during pregnancy or
childbirth and erythrocytes (red blood cells) in the baby's blood pass. There
are Rh antigens belonging to the baby on these erythrocytes. The mother
responds by producing anti Rh antibodies. The baby in this pregnancy is not
harmed, but if the baby is Rh (+) in the next pregnancy, anti-Rh antibodies
formed in this first pregnancy in the mother's blood pass to the baby and cause
the erythrocytes to break down in the baby's blood and anemia (anemia) in the
baby.
The following conditions that may occur during birth and
pregnancy may cause infant blood to pass to the mother and the mother to form
antibodies against them. These
situations are:
Interventions such as miscarriage, ectopic pregnancy, amniocentesis,
CVS, cordocentesis are performed.
In these cases, Anti-D needle should be applied within 72
hours in order to prevent the mother from being affected. This needle is
usually made from the hip into the muscle (intramuscular). Although the needle is
recommended to be made within 72 hours, it is reported that it can be done
within 14-28 days.
In patients with blood incompatibility (Rh / rh
incompatibility), if the indirect coombs test (ICT) is negative in the first
control, the ICT should be repeated at weekly intervals from the 20th week due
to the possibility of developing Rh isoimmunization in the antenatal period.
Pregnant women with a negative ICT should first receive prophylaxis with 300
micrograms of anti-D gamma globulin at week 28. The purpose of prophylaxis
during this period is to meet the fetus-mother bleeding that may occur during
the 12-week period until delivery. The most important period for prophylaxis in
a non-immunized pregnant woman is birth. Following birth, direct coombs test (DCT)
and infant blood group should be studied from the baby's cord blood. If DCT is
negative and the infant blood group is Rh (+), anti-D immunoglobulin should be
repeated. If the baby's blood group is positive after delivery, the anti-D
globulin needle should be used again within the first 72 hours. This prevents
the formation of antibodies in the mother and prevents the next pregnancy from
being affected by these antibodies. In Rh incompatibility, no problem occurs in
the first pregnancy.
In the case of blood incompatibility, if the baby is
affected, anti-Rh antibodies passed through the mother cause the baby's blood
cells to break down and precipitate. In this case, anemia, that is, anemia is
seen in the baby. Accordingly, the condition called hydrops fetalis is detected
in the baby on ultrasound. It is the cause of fluid hydrops accumulating in
heart failure and body cavities as a result of anemia in the baby. Depending on
the severity of the disease and the amount of blood cells destroyed, the baby
may even experience death in the womb.
If the ICT test is positive, titration should be studied.
There is no risk for the fetus in titrations of 1/16 and below in the
intrauterine period. In this case, it will be sufficient to repeat the ICT at
2-4 week intervals. Pregnancy is not intervened unless ICT positivity is above
1/16. Prophylaxis will not be required only since isoimmunization will be
improved. If the titration is 1/16 or higher, advanced investigations such as
amniocentesis, cordocentesis and USG should be started to investigate the
severity of the effect. If the disease is serious, it may be necessary to
change the baby blood in the womb. Amniotic fluid taken by amniocentesis is
evaluated by the optical density measurement method (DOD450 - depending on the
density of bilurib) and is divided into a risk group in the curve called Liley
curve. Those who entered the 2nd or 3rd zone in the Liley curve are severely
affected and have a blood transfusion indication. With cordocentesis,
hemoglobin measurement and blood transfusion can be done to the baby.
Conditions
that can cause Rh alloimmunization in the mother:
These are the conditions that can cause Rh (-) mother to form
Rh antibody.
- Blood transfusion
- Blood cell transmission from Rh (+) baby to mother during
pregnancy or childbirth
- Spontaneous or voluntary abortion
- Abortion
- Ectopic pregnancy
- Early separation of the placenta (baby's wife)
- Impact and traumas that may come to the womb
- Amniocentesis (Taking baby water from the womb)
- CVS (Chorionic villus biopsy)
- Cordocentesis (Taking blood from baby's cord)
- External cephalic version
Is there any conflict related to A, B, O blood groups?
There may also be incompatibility between A and B, O blood
groups between mother and baby. This conflict, which is seen in 20 percent of
all pregnancies, is theoretically possible, but in practice it is not important
because the effect is very mild. Therefore, in practice, ABO incompatibility is
not investigated and no medication is used to prevent this. This type of
mismatch can be mentioned when the mother is 0 group, fetus is A1 or B group.
In this case, the reasons for being affected and the anemia of practice being
insignificantly mild: In this case, antibodies are mostly in the structure of
IgM that cannot cross the placenta, and a small number of antibodies are formed
in the structure of IgG. ABO antigens are found in small amounts on the surface
of erythrocytes. ABO antigens are found in all tissues in the fetus, so
antibodies bind to all tissues and the effect on erythrocytes is minimal.
If there is an incompatibility and Rh incompatibility between
ABO blood groups between the mother and fetus, ABO incompatibility reduces the
severity of Rh incompatibility. Because ABO antibodies passing from mother to
fetus cause partial damage of Rh antigens in fetus.
What is
Grandmother Theory?
According to the situation in this interesting theory, the
source of Rh antibodies passed from mother to baby is the baby's grandmother.
The baby is rh (+), mother rh (-), granny rh (+).
Here, fetomaternal bleeding during the grandmother's
pregnancy caused the fetus to form anti-d antibodies (as opposed to normal). In
other words, the fetus has sensitized in the womb. When the fetus reaches
adulthood after birth and becomes pregnant, if her baby is rh (+), this time
she will pass on the anti-d antibodies that have occurred before, to her own
baby, and the baby may develop a disease.
ADDITIONAL
INFORMATION:
- Kleihauer-Betke test (K-B test) is a test that
quantitatively shows the amount of fetomaternal bleeding.
- Erythrocyte Rosette Test is a test that qualitatively shows
fetomaternal hemorrhage.
Among the interactions that can cause severe hemolysis, the
most common Anti-D antigen is, while the most severe is the Anti-Kell interaction.
Although the anti-Kell interaction is more severe, hemolysis occurs less
because anemia with Anti-Kell occurs not only by the hemolysis mechanism but
also by the destruction of the erythrocyte precursors. Therefore, there may be
no correlation between the degree of anemia and the level of amniotic fluid
biluribin and Anti-Kell antibody titer in Anti-Kell hemolysis.
- Apt test is a test to determine whether the blood in the
newborn's stool or stomach content (vomit) belongs to the mother or baby. It is
made by making use of HbF being more resistant to alkali. NaOH is used for the
test.
-UMBILICAL CORD AROUND BABY’S NECK
-LOW AMNIOTIC FLUID IN PREGNANCY
-HIGH AMNIOTIC FLUID IN PREGNANCY
-PREMATURE MEMBRANE RUPTURE
-FETAL DISTRESS
