When you’re pregnant, your body goes through a lot of changes to support the growth and development of your baby. One of those changes is the production of antibodies in your blood.
What Are Antibodies?
Antibodies are proteins produced by your immune system to fight off infections. They’re specific to each type of infection, so your body can develop antibodies to protect you from future infections of the same kind.
Antibodies During Pregnancy
During pregnancy, your body produces antibodies against:
- The Rh factor
- The ABO blood group
- Infections that you may have come into contact with
The Rh Factor
The Rh factor is a protein found on red blood cells. If you have the Rh factor (Rh-positive), your blood is compatible with blood from people who don’t have the Rh factor (Rh-negative).
However, if you’re Rh-negative and your baby is Rh-positive, your body may produce antibodies against the Rh factor. This can cause a condition called Rh incompatibility, which can lead to anemia and other health problems for your baby.
The ABO Blood Group
The ABO blood group is another protein found on red blood cells. There are four main blood groups: A, B, AB, and O.
If you’re pregnant and you have a different blood group than your baby, your body may produce antibodies against the antigens on your baby’s red blood cells. This can cause a condition called ABO incompatibility, which can lead to hemolytic anemia in your baby.
Infections
During pregnancy, you may also produce antibodies against infections that you may have come into contact with. This can help protect your baby from those infections.
How Are Antibodies Tested During Pregnancy?
Antibodies are tested during pregnancy with a blood test. This test is usually done at your first prenatal appointment and may be repeated later in your pregnancy if you’re at risk for Rh incompatibility or ABO incompatibility.
What Do the Results Mean?
The results of your antibody test will tell you if you have antibodies against the Rh factor, the ABO blood group, or any infections.
If you have antibodies against the Rh factor, you will need to receive a medication called Rh immunoglobulin (RhIg). RhIg will prevent your body from producing antibodies against the Rh factor and will help protect your baby from Rh incompatibility.
If you have antibodies against the ABO blood group, your doctor will monitor your baby for hemolytic anemia. If necessary, your baby may need to receive a blood transfusion.
If you have antibodies against an infection, your doctor will monitor you and your baby for any signs of infection.
Conclusion
Antibodies are an important part of your immune system and play a vital role in protecting you and your baby during pregnancy. If you have any questions about antibodies during pregnancy, talk to your doctor.
Additional Information
For more information on antibodies during pregnancy, visit the following websites:
- Centers for Disease Control and Prevention
- American College of Obstetricians and Gynecologists
- March of Dimes
Table 1: Antibodies Tested During Pregnancy
| Antibody | What it protects against | |—|—| | Rh antibody | Rh incompatibility | | ABO antibody | ABO incompatibility | | Infection antibody | Infections |
Table 2: Rh Incompatibility Rates
| Population | Rh incompatibility rate | |—|—| | United States | 1 in 100 pregnancies | | Europe | 1 in 200 pregnancies | | Asia | 1 in 500 pregnancies |
Table 3: ABO Incompatibility Rates
| Blood group | Incompatibility rate | |—|—| | A | 1 in 20 pregnancies | | B | 1 in 10 pregnancies | | AB | 1 in 5 pregnancies | | O | 1 in 1 pregnancy |
Table 4: Infections That Can Be Detected by Antibody Testing
| Infection | Antibody | |—|—| | Rubella | Rubella antibody | | Toxoplasmosis | Toxoplasma antibody | | Cytomegalovirus | Cytomegalovirus antibody | | Herpes simplex virus | Herpes simplex virus antibody |
