Blood type of a child

The blood circulates throughout the body, carrying useful elements and oxygen to all cells. There are no substitutes for blood, so many people donate blood to help those who need it.

Each drop of blood contains red blood cells (erythrocytes), white blood cells (leukocytes), platelets, and plasma. In addition, there are antigens and antibodies in the blood. Antigens are attached to the surface of red blood cells, and antibodies are in the plasma.

Antigens and antibodies play an important role in the immune system. Antibodies are produced by leukocytes and are contained in blood plasma. If antibodies recognize the donor blood cells as foreign, they will attack them.

Even though blood consists of the same elements, there are at least 33 systems by which blood is divided into different types. Your blood type depends on the genes that you inherited from your parents.

The most common systems are the ABO system and the Rh system.

ABO blood system

The blood type depends on which antigens are on the surface of the red blood cells. There are 2 types of such antigens: A and B. Depending on the combination of these antigens or their absence, there are 4 blood groups:

Blood group O – red blood cells have neither antigen attached to the surface. The plasma contains anti-A antibodies and anti-B antibodies.

Blood group A – the surface of red blood cells contains antigen A. The plasma has anti-B antibodies.

Blood group B – the surface of red blood cells contains antigen B. The plasma has anti-A antibodies.

Blood group AB – red blood cells have antigens A and B. There are no antibodies in the plasma.

Antibodies and antigens. Which blood types are compatible for transfusion?

It is very important to select the correct blood type for transfusion. If the plasma contains antibodies to donated blood, the donor cells will be destroyed, which leads to the formation of blood clots and blockage of blood vessels.

For example, if someone with type A blood is given type B blood, then anti-B antibodies from type A blood will attack type B cells. That is why a person with type A blood should never be given a type B blood, and vice versa.

People with type O blood group are considered universal donors, since their blood does not have antigens A and B.

Blood group AB is considered a universal recipient, that is, it can accept any donor blood, since plasma does not contain antibodies that can recognize antigens A and B.

Genetics. Can a child's blood be different from parents'?

Blood type is inherited. The child inherits 23 pairs of chromosomes – 23 from the father, and 23 from the mother. Chromosomes contain genes. Each gene is presented in two versions (alleles). One version of the gene is from the mother, and the second is from the father.

Your blood type depends on which version of the gene you received from your parents.

For example, a mother has two versions of the gene – A and O, and a father has B and O. They can transmit either of their two versions to their child. That is, the child may have the following combinations: AB, AO, OV, OO.

Below is a blood group table for each allele combination:

Blood Compatibility

The ABO system is the most widely known, but the Rh system is also crucial for safe transfusions. The Rh system refers to another antigen, the Rh factor, present or absent on red blood cells. People with the Rh factor are Rh positive (Rh+), while those without it are Rh negative (Rh-). Similar to the ABO system, incompatibility can occur if Rh- blood receives Rh+ blood.

Beyond ABO and Rh, other blood group systems exist, like the MNS system and the Duffy system. These systems have less impact on transfusions but can be relevant in specific cases.

Knowing your blood type is vital for safe blood transfusions, but it might also hold some clues about your health. Studies suggest potential associations between blood types and certain conditions. For instance, people with type O blood may have a lower risk of stomach ulcers, while those with type A might be more susceptible to blood clots. However, these connections are complex and require further research.

Blood types are not just about transfusions. They can play a role in pregnancy too. If a Rh- mother carries a Rh+ baby, their blood can mix, potentially causing hemolytic disease of the newborn (HDN). Fortunately, with proper prenatal care and medication, HDN is largely preventable.

The discovery of blood types revolutionized medicine. By understanding blood compatibility, doctors can ensure safe transfusions, a life-saving procedure for many. Research on blood types continues to unveil their potential impact on health, making blood type a fascinating aspect of human biology.