Hemolytic disease of newborns is a disease that is due to the incompatibility of the blood of the mother and the fetus according to various antigens. More often it develops when incompatibilities in the rhesus factor.
Content
Rh Factor - this is a special substance contained in the blood of a person. It is obliged by his name to an animal - Macake-Rh, from which it was first discovered. It is proved that the lack of this substance in the blood of a woman can negatively affect the fate of her pregnancy.
The rhesus factor (D-antigen) is a protein located on the surface of the erythrocytes («Red blood taurus» - Blood cells bringing oxygen to fabrics). Accordingly, the rhesus is a positive person, on the erythrocytes of which contains a Rh factor (about 85% of the population), and otherwise, if this substance is absent, such a person is a rhesus-negative (10-15% of the population). Rhow-affiliation of the fetus is formed in the earliest period of pregnancy.
Conflict probability
The probability of a rhesus conflict during pregnancy (the incompatibility of the mother and fetus on the D-antigen) occurs if the future mother Rus-negative, and the future dad rhesus-positive and the child inherits the Rh-positive gene from the Father.
In the event that a woman is reserves-positive or both parents rezes-negative, the rhesus conflict does not develop.
Why arises Res-conflict
The cause of the rhesus conflict, or rhesib-sensitization, during pregnancy is the penetration of the reserves-positive erythrocytes of the fetus in the bloodstream of the rezes-negative mother. In this case, the mother's body perceives the erythrocytes of the fetus as foreign and reacts to them the production of antibodies - connections of the protein structure (this process is called sensitization).
To be clear why antibodies are formed in the body, we will make a slight digression. Antibodies are protein (plasma immunoglobulins) in human blood and warm-blooded animals, synthesized by lymphoid tissue cells under the influence of various antigens (alien agents). Interacting with microorganisms, antibodies prevent their reproduction or neutralize the toxic substances released by them; They contribute to the generation of immunity, that is, antibodies work against antigen. The immunization process (sensitization) in the case of rhesus incompatibility can occur, starting from 6-8 weeks of pregnancy (it is on this time that the erythrocytes of the fetus in the blood flow of the mother are found); The effect of mothers antibodies is aimed at eliminating the erythrocytes of the fetus.
At the first meeting of the immune system of the future mother with reserves-positive erythrocytes of the fetus, antibodies (immunoglobulins) of class M are produced, the structure of which does not allow them to penetrate the placenta; Thus, these antibodies do not affect developing fruit. After this meeting in the immune system of the mother form «Memory cells», Which when repeated contact (occurring under the following pregnancies) produces antibodies (immunoglobulins) of class G, which penetrate the placenta and can lead to the development of hemolytic disease of the fetus and a newborn . Once appearing, class G antibodies remain in the body of a woman for life. Thus, rhesus antibodies in the organism of a rhesus-negative woman can appear with an artificial or spontaneous interruption of royal or ectopic pregnancy, after the first birth at the birth of a rhesus-positive child. Rhose-sensitization is also possible if the woman has ever been transfused blood without taking into account the Rh. The risk of reserves-sensitization increases in subsequent pregnancies, especially in the case of interrupting the first pregnancy, bleeding during pregnancy and childbirth, manual branch of the placenta, as well as in the delivery of the cesarean section. This is explained by the fact that the listed situations in the blood flow of the mother falls in a large number of reserves-positive erythrocytes of the fetus and, therefore, the Mother's immune system reacts to the response formation of a large number of antibodies.
According to medical literature, after the first pregnancy, immunization occurs in 10% of women. If during the first pregnancy, the immunization reserves did not occur, then upon subsequent pregnancy, the probability of immunization is again 10%. Rhose-antibodies circulating in the bloodstream of the future mother do not harm her health, but penetrating through the placenta may provide serious danger to the fetus.
