For centuries our ancestors could not predict what their child would be like. We live with you at a time when, thanks to the development of science, it is not at all difficult to know in advance the gender, color of hair and eyes, predisposition to diseases and other features of the future baby. It became possible and to know the blood type of the child.
In 1901, the Austrian physician, chemist, immunologist, infectious disease specialist Karl Landsteiner (1868-1943) proved the existence of four blood groups. Studying the structure of erythrocytes, he discovered special antigen substances of two varieties (categories), which designated A and B. It turned out that in the blood of different people these antigens are found in different combinations: one person has antigens only in category A, the other has only B , the third - both categories, the fourth - they are not at all (the red blood cells of such a blood scientists designated as 0). Thus, four blood groups were singled out, and the blood division system itself was named AB0 (read "a-be-nol"):
- I (0) - without antigens A and B;
- II (A) - antigens A;
- III (AB) - antigens B;
- IV (AB) - antigens A and B.
This system is used to this day, and the discovery by scientists of the compatibility of blood groups (with certain combinations of red blood cells there is a "gluing" of red blood cells and rapid blood clotting, and in others - no) allowed to make a procedure safe, such as blood transfusion.
How do I know the baby's blood type?
Genetic scientists have established that the blood group and other traits are inherited by the same laws - the laws of Mendel (named after the Austrian botanist Gregor Mendel (1822-1884), who in the middle of XIX formulated the laws of inheritance). Thanks to these discoveries, it became possible to calculate which blood group the child inherited. According to the law of Mendel, all possible variants of inheritance of a blood group by a child can be presented in the form of a table:
From the table above it is clear that it is impossible to determine with absolute accuracy, whose blood group the child inherits. However, we can confidently talk about which blood groups the child should not have a specific mother and father. The exception to the rules is the so-called "Bombay phenomenon". Extremely rare (mainly in Indians) there is a phenomenon where a person in genes has antigens A and B, but he himself does not have blood in his blood. In this case, it is impossible to determine the blood group of a unborn child.
Blood group and Rh factor of mother and child
When your child is given a blood group test, the result is written as "I (0) Rh-", or "III (B) Rh +", where Rh is the Rh factor.
The Rh factor is a lipoprotein, which is present in red blood cells in 85% of people (they are considered Rh positive). Accordingly, 15% of people have Rh-negative blood. The Rh factor is inherited all according to the same laws of Mendel. Knowing them, it's easy to understand that a child with Rh-negative blood can easily appear in Rh-positive parents.
It is dangerous for the child such a phenomenon as Rh-conflict. It can occur if, for some reason, the Rh-positive red blood cells of the fetus enter the body of the Rh-negative mother. The mother's body begins to produce antibodies, which, getting into the blood of the child, cause hemolytic disease of the fetus. Pregnant women who have antibodies in their blood are hospitalized until the very birth.
Maternal and child blood groups are rare, but may also be incompatible: mainly when the fetus is IV group; and also when in group I or III the group and in the fetus group II; in the mother I or II group and in the fetus III group. The probability of such incompatibility is higher if the mother and father have different blood groups. The exception is the first blood type of the father.