ABO blood group compatibility for marriage

Couple doing blood transfusion after testing for blood type compatibility

Blood group types often don't affect the strength of marital relationships among couples.

But, having a compatible blood group with your partner makes it easy to give or receive blood from them in emergencies, e.g., in cases of an accident where one partner has lost a lot of blood or when a kidney transplant is needed.

Knowing your blood group type will also give you a great insight into how your blood group and that of your partner may affect your health status. Studies have shown a link between blood group types and certain health conditions.

Learning about your blood groups will also help you know the possible blood types for your biological children because they will inherit the genes from you. It may also help in determining a child's paternity.

This article explains all you need to know about the ABO blood group compatibility for marriage, the antigens, and the antibodies that differentiate one blood type from the other. It will also discuss a bit about the rhesus blood factor system and how blood types are inherited.

But first, it will discuss what antigens and antibodies mean because it is the unique combination of antigens and antibodies that differentiates blood and groups them into types.

Body antigens and antibodies

Antibodies are proteins found in the blood plasma, which the immune system (white blood cells) produces to fight against a foreign agent.

They are part of your body's natural defense. Once your body notices an invasion by a foreign agent such as germs, it mobilizes the antibodies to fight against the foreign agent.

On the other hand, antigens are molecules found on the surface of red blood cells and can be either proteins or sugars. Among the functions of antigens in the blood are:

  • To maintain the structure of red blood cells.
  • To transport other molecules in and out of the cells
  • To detect unwanted to abnormal cells that can cause sickness

Generally, scientists classify blood types using two types of antigens: These two play a role in determining blood types and blood group compatibility.

Both antigens and antibodies play an important role in the immune system's defence mechanism.

The ABO Antigens blood group system

Scientists use two main types of antigens to classify blood types, one of which is the ABO antigens.

The ABO blood group is a system that classifies blood types according to the different antigens present on the surface of the red blood cells and the antibodies in the blood plasma.

ABO blood group chart

With this, the ABO blood group system is classified into four:

Group A: In this blood group, A antigen is present on the surface of the red blood cells while the blood plasma contains an anti-B antibody. This means that the anti-B antibody in the plasma will attack any blood cell containing the B antigen.

Group B: B antigen is present on the surface of red blood cells for this blood group. Also, the plasma has an anti-A antibody, which means it would launch an attack on any blood cells that contain A antigen.

Group AB: The AB group has red blood cells with both A and B antigens. However, the blood plasma has neither anti-A nor Anti-B antibodies. Hence, individuals with this blood type can receive blood from a partner with any ABO blood type. (compatible blood groups).

Group O: Group O blood plasma contains anti-A antibodies and anti-B antibodies (opposite of Group AB). However, the surface of the red blood cells doesn't contain A antigen or B antigen.

Since Group O has both anti-A and anti-B antibodies, it can't receive blood from any group with Antigen or B antigen. However, since its blood cells do not contain A antigen or B antigen, it can give out blood to any ABO blood type. People with blood group O are referred to as universal donors.

Understanding this will help couples understand more about blood group compatibility for marriage.

The Rh antigen is the second classification and third type of antigen, which scientists use to classify blood types. It is either you have the Rh antigen (meaning your blood type is positive "Rh+"), or you don't (which means your blood type is negative, "Rh-").

Photo source: Shutterstock

Understanding blood group types for marriage compatibility

The rhesus factor further divides the ABO blood group system into eight different blood types. Understanding the blood group types is key to understanding blood group compatibility for marriage.

  • A+: A positive is one of the most common blood types, and someone bearing this blood type can give out blood to a spouse who is A positive (A+) or AB positive (AB+).
  • A-: A negative is a rare blood type. However, a person with this blood type can give out blood to a spouse with an A or AB blood type (both negative and positive).
  • B+: B positive is a bit common but not as much as A positive. Individuals with this blood type can donate blood only to B positive (B+) or AB positive (AB+) spouses.
  • B-: People with B negative blood type can donate blood to a partner with B+, B-, AB+, and AB- blood types.
  • AB+: People with AB-positive blood types are known as universal recipients because they can receive any blood plasma type. But, they can only donate to the AB+ blood group.
  • AB-: AB negative is the least common blood type. People who have this blood type can give out blood to a partner with blood groups AB+ and AB- and can receive from all negative blood groups.
  • O+: Just like A positive, O positive is quite common too. Someone with this blood type can give out blood to a spouse with any positive blood group. They can only receive blood from O- and O+.
  • O-: Someone with O negative blood type can give blood to anyone. However, they can only receive from a spouse with an O-negative.

Studying the blood group matching table or the blood group chart for marriage will help you understand better which blood type your blood is compatible with.

Rhesus factor incompatibility can also affect some marriages because when an Rh-negative mother gives birth to an Rh-positive child, her antibodies can attack the child's red blood cells leading to side effects that can range from mild to severe.

Taking care of the sick baby and the medical costs can put a strain on the parents. It would also be stressful for the mother, who should normally be taking time to heal and recover from the child's delivery.

How blood types are inherited

Blood types are inherited just the way you inherit the genes for your hair or eye color. The ABO blood group is inherited in an autosomal codominant manner, as explained further below.

Everybody has two ABO genes and will have to donate one of those genes to their biological children. While the O gene is recessive, the A and B genes are dominant. This means if an O gene pairs with a B gene, the resulting blood type will be B.

Two different enzymes make the A and B antigens on the surface of red blood cells. The enzymes are encoded by different alleles of the same gene. The A allele codes for the enzyme that makes the A antigen, while the B allele codes for the enzyme that makes the B antigen.

In the case of the O allele, it codes for a protein that isn't functional.

Everyone inherits one allele from each parent. The combination of the two inherited alleles will determine your blood type. However, it is important to understand that A and B alleles are dominant over O.

This means if a child receives an A allele from one parent and an O allele from the other parent, the child's genotype will be A. If a child receives allele B from one parent and O from another, the child's genotype will be B. A child will only have genotype O if they receive an O allele from both parents.

Role of blood types in determining paternity

In cases where one parent is not sure if a child is their biological child or not, they will often be advised to take a paternity test. A paternity test is a definitive test to determine if your baby's genetic make-up matches yours.

However, not everyone can afford to run a DNA paternity test. In some countries, the cost of a DNA paternity test is high. Checking the child's blood type to see if it matches yours and that of the mother may give insight into the paternity status.

For instance, if both parents of a child have blood group O, it is assumed that their children should have blood group O. If one parent has blood group B and the other has blood group O, the possible blood groups for the children should be O or B. The table above gives more insight into this.

It often works this way except in very rare cases where gene mutations occur.

Also, note that even though ABO blood typing can be used to exclude a man from being a child's father, it cannot be used to tell for sure if a man is a child's father.

So, while this method can provide some insights, it is not sufficient or valid for paternity testing. If you are not sure of a baby's paternity status, it is often best to take a DNA paternity test.


It is important for intending couples to know their blood group types in that way; they can know if their blood group match that of their spouse. Blood group compatibility in marriage makes it easier to transfuse blood from one partner to the other in emergency cases.

Also, blood types can give insight into the possible alleles your children will inherit from you. Even though having a DNA paternity test offers a sure way to know your baby's blood type, knowing your blood type and that of your partner can help you narrow down the possibilities.

If you are not sure of your blood type or that of your partner, you can speak to your doctor or simply visit a clinic near you so they can carry out a blood typing test on you and your partner.

Find out how to know your blood group type and the relationship between blood groups and disease risks.


  1. Bugert, P. et al. (2012). Blood group ABO Genotyping in paternity testing.
  2. Dean laura. 2015. ABO blood group.
  3. National Health Service UK. (2020). Blood groups.
  4. University of Utah. (n.d.). Genes and blood type.