The relationship between blood group of parents and children

What is the relationship between the blood types of parents and children, the blood group of the children according to the father or mother, the inheritance of blood group from parents to children? If so, what happens and how is it treated?

In the human body, there are about 4-6 liters of blood. Blood is made up of different types of cells in plasma, including:
Red blood cells: Deliver oxygen to various tissues in the body and remove carbon dioxide. White blood cells: Destroy invading agents and fight infection. Platelets: Helps in blood clotting. Plasma is made up of proteins and salts. The combination of protein molecules in the blood produces antigens and antibodies, which are what distinguish one person's blood from another. Antigens live on the surface of red blood cells and antibodies are present in the plasma. The combination of antigens and antibodies in the blood is the basis for determining blood group.
Although there are at least 33 blood collection systems, only two are widely used, the ABO and Rh+ (positive) or Rh- (negative) blood group systems. These two groups combine to form 8 basic blood groups, namely: A+, A-, B+, B-, AB+, AB-, O+, O-.

Blood type is determined by genetics. Each person inherits genes from their parents, one from their mother and one from their father - to create a pair. Therefore, blood groups of parents and children are closely related.
2.1 Inheritance of blood type from parent to child - ABO system With the ABO system, one person can inherit gene A from one parent and gene B from the other, resulting in blood type AB. Or it is also possible to get B antigens from both parents and make BB or B blood type.
On the other hand, O blood type doesn't contain any antigens and doesn't affect A and B blood types. So , if you inherit O from one parent and A from the other, your child's blood type will be A. Or both parents have blood type A or B but can still give birth to a child with type O blood if the child carries the O gene.
2.2 Inheritance of blood type from parent to child - Rh factor Blood is also measured according to the Rh factor. This is another antigen found on red blood cells. If the red blood cells have antigens, it is Rh positive or Rh+, otherwise it is Rh-.
Rh factor is an inherited protein, so passing on blood type from parent to child will determine Rh+ or Rh-, but the most common is Rh+.

Rh+ or Rh- usually doesn't affect health but can affect pregnancy. If the mother's blood type is Rh- but the blood type inheritance from parent to child is Rh+, it should be considered. Because the blood cells from the Rh+ baby will follow the Rh- mother's blood stream to trigger the mother's immune response to form antibodies that attack the baby's Rh+ red blood cells. This phenomenon is called blood type incompatibility between mother and child.
So at your first prenatal visit, your doctor always recommends a blood type and Rh factor screening test. If you have Rh- blood type, your doctor will order the blood test again at your next prenatal visit to check for antibodies against Rh that have formed in your body. It also means that the child has Rh+ blood type.
If the doctor determines that the blood type is passed from parent to child with possible Rh factor incompatibility, the mother needs to be closely monitored during pregnancy and may even require extra care.
Although maternal and fetal blood usually do not mix during pregnancy, a minimal amount of maternal and infant blood can come into contact during delivery. So, if there is an Rh incompatibility, then the mother's body can make Rh antibodies to fight the Rh factor.
These antibodies will not cause problems for a baby with Rh+ blood type in the first pregnancy. But it can cause problems in subsequent pregnancies, especially if the baby has Rh+ blood type.
If blood type inheritance from parent to child occurs Rh incompatibility in first pregnancy and Rh factor incompatibility in second and subsequent pregnancies, antibodies made in the mother's body can damage the baby's red blood cells. The baby may then need a red blood cell transfusion while in the womb or soon after birth.

If Rh incompatibility has been diagnosed, your doctor will probably recommend Rh immune globulin (RhoGAM) during the seventh month of pregnancy and then repeat within 72 hours after delivery if the genetic group blood from parent to child confirmed to be Rh+ at birth.
Rh immune globulin contains Rh IgG antibodies, so the mother's body will not react to the baby's Rh+ cells and she will not produce anti-Rh antibodies.
In short, blood types of parents and children are closely related, the blood type of children is inherited from parents. Therefore, each person's blood group is determined before birth and cannot be changed after birth.

Reference source: webmd.com - healthline.com