Serological conflict

Proven content

Serological conflict is a hemolytic disease of the newborn. It consists in the presence of antigenic features in the fetal red or white blood cells not found in the mother. The conflict most often occurs during labor, when the baby’s blood mixes with that of the mother.

Serological conflict – definition

Serological conflict resembles a defense mechanism against viruses – immunity is developed to destroy the enemy. While it has a beneficial effect in the case of pathogenic microorganisms, in a serological conflict the effect is quite the opposite, as it makes the child sick.

As a result of inheritance, the fetus receives antigenic features from both the mother and the father. During pregnancy, as a result of the entry into the mother’s circulation of fetal blood cells with the father’s antigenic features (which the mother does not have), the mother starts to produce antibodies against these antigens.

The most famous and important example of a serological conflict is the difference in Rh antigens of red blood cells between the fetus and the mother. The production of antibodies in this system in the mother’s circulation occurs when the fetus inherits the father’s “D” (Rh +) antigen and the mother has the “d” (Rh-) antigenic trait.

The resulting anti-Rh antibodies pass into the fetal circulation and damage the fetal blood cells, which can lead to the so-called haemolytic disease of the fetus (serological conflict) significant damage manifested, inter alia, by generalized edema.

Serological conflict – how does it arise?

Each person has their own blood type (A, B, AB or 0), but not only blood types differ from each other. Most of the population on the surface of red blood cells has the D antigen (not all have it). The D antigen originates from the Rhesus monkeys, hence the name Rh factor. There are more people who are Rh + (85%) as opposed to Rh- (around 15%).

The conclusion is that future pregnant women mainly have the RH + factor, which means that they are not in danger of a serological conflict. If future mothers had the RH- factor, they would be at risk of its occurrence. It is then important what factor the father has, if also negative (there is no threat), because the factors of father and mother are the same. Therefore, a serological conflict has a chance to arise when the mother has RH- and the father RH + and the child inherits the factor from the father (this happens in 60% of cases).

Serological conflict and hemolytic disease

Usually ‘new babies’ born to a woman are at risk of haemolytic disease because antibodies produced during the first pregnancy remain in the mother’s bloodstream and can pass into the baby’s blood after the placenta is formed. In the blood, antibodies bind with erythrocytes, causing their destruction, i.e. haemolytic disease. Hemolysis leads to increasing anemia, and the fetus, wanting to cope with the loss of blood cells, increases their production not only in the bone marrow, but also in the spleen and liver, which consequently become enlarged. Unfortunately, the newly formed blood cells are not able to perform their functions well, which causes the increase of anemia and hypoxia, which causes the blood vessels to leak water to the outside. This situation leads to the most dangerous form of the disease, i.e. fetal generalized swelling.

The ailment is manifested by swelling of the skin and subcutaneous tissues. There is a large amount of fluids in the abdomen, which makes internal organs enlarged, including the heart, which becomes inefficient. Fetal generalized swelling often ends in miscarriage or death of the newborn immediately after delivery.

What is the result of decaying erythrocytes?

Bilirubin is formed, which is a substance formed by the breakdown of hemoglobin released from dead red blood cells. It has a yellow color. It accumulates in the skin and tissues of the newborn, which cannot cope with their excess, which causes yellowing of these tissues. The acute form of hyperbilirubinemia lead to the serious complication it is jaundice of the subcortical testicles. It is caused by the accumulation of excess bilirubin in the brain and spinal cord, which in turn leads to extensive damage to these structures. The damage may contribute to disorders such as hearing loss or cerebral palsy. However, with the right treatment, it can be prevented.

When does fetal blood enter the mother’s bloodstream?

In order for antibodies to form, a minimum of 0,2 ml of fetal blood must enter the pregnant woman’s bloodstream. All future mothers should have a defined blood group, Rh factor, and (if Rh-) level of antibodies attacking the fetal red blood cells by the 12th week of pregnancy.

The blood of the fetus enters the mother’s body due to:

1. detachment of the placenta,
2. hemorrhages
3. cesarean section,
4. ectopic pregnancy,
5. miscarriages
6. operations / procedures inside the uterus,
7. prenatal tests,
8. surgical delivery, for which forceps are used, for example.

Early detection of serological conflict

In the case of the antigenic configuration between the mother and father of the child, it is advisable – periodic tests to detect anti-Rh antibodies should be performed, bearing in mind that the development of a serological conflict in the fetus usually does not occur in the first pregnancy. If the antibodies do not appear and the child has inherited the blood type RhD+ after the father, the mother should receive the so-called anti-“D” serum. It is an obligatory prophylactic procedure to prevent the emergence of an Rh serological conflict in the next pregnancy.

The detection of dangerous antibodies in a woman is an indication for special medical care. With a small amount of antibodies, it is enough to repeat the test once a month, while if their titer is high – invasive tests, e.g. aminocentesis, cordocentesis, are necessary. They are also performed when there is a suspicion that a child has a haemolytic disease.

Aminopuncture – it is a test consisting in making an incision through the abdominal wall of the amniotic cavity in which the fetus is located. About 20 ml of amniotic fluid is collected for examination under ultrasound control. In this fluid, the concentration of bilirubin is assessed. However, it should be remembered that this test does not accurately reflect the severity of the haemolytic disease.

Cordocentesis – is a much more accurate and more frequently used test to obtain umbilical cord blood. As in ultrasound-guided aminopuncture, umbilical vessels are incised with a thin needle and about 0,5-1 ml of blood are collected. Then, blood analysis gives an answer to the question of the degree of anemia we are dealing with and the blood type of the fetus. This study allows you to plan further proceedings.

Treatment of serological conflict

Treatment is initiated when the fetus is diagnosed with severe anemia. The best therapeutic method is intrauterine blood transfusion, which is similar to cordocentesis, with the difference that after puncturing the umbilical cord, the blood is given to the toddler and not collected. For the transfusion to be successful, it is necessary to use D-antigen-deficient blood cells, i.e. those that are indifferent to the attack of antibodies. After about 3-4 transfusions, the baby starts to function properly thanks to the transfused blood. His own red blood cells have been destroyed and his body is not producing any more.

Thanks to the transfusion, there is no need for frequent blood transfusions. However, the treatment itself lasts until the toddler reaches maturity for life outside the womb, i.e. until 35.37. week of pregnancy. Then the doctors decide to induce labor, preferably natural. After birth, the child is still treated with phototherapy and subsequent transfusions, depending on the severity of the haemolytic disease.

Another equally effective and more modern method of treating hemolytic disease is administration of human immunoglobulins from the 12th week of pregnancy until the delivery itself. The immunoglobulins bind to the antibodies produced by the mother, rendering them harmless. Although this therapy brings good results, it is very expensive, making its widespread use practically impossible.

Serological conflict and prevention

There is also a possibility of prophylactic treatment during pregnancy by administering a specially adapted and purified anti-“D” serum, both in cases of imminent miscarriage, preterm labor, operations on the uterus during pregnancy (e.g. collection of amniotic fluid for examination), and without it type of threats – as an intra-pregnancy preventive measure between the 28th and 30th week of pregnancy directed against a potential serological conflict. This injection is a natural product made from the blood that stops the body from producing harmful antibodies. It is inhibited by destroying any blood cells in the fetus that could enter the mother’s bloodstream. When the D antigen is absent, no antibodies can be made against it.

Medicine tries to prevent the emergence of a serological conflict at all costs. Prophylaxis in the form of administration of purified anti-D serum is quite effective, as it is about 96-98%. Other methods to reduce the risk of serological conflict include:

1. checking the blood group and Rh factor at the beginning of pregnancy,
2. testing the gamma anti-d preparation within two days after childbirth,
3. tests performed by the father (the child may inherit the Rh blood group from him),
4. informing the doctor about a miscarriage or termination of pregnancy (after this type of surgery, the patient must be given immunoglobulin).
5. performing tests for the presence of antibodies (they should be performed three times during the whole pregnancy).

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