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Serological conflict is a disease that expectant mothers are most afraid of. Which women are more likely to develop it? Can it be prevented? Find out why one of the most important tests during pregnancy is the anti-Rh antibody test.
What is Rh factor?
There are a number of different proteins found on red blood cells (erythrocytes). They decide whether you have blood type A, B, AB or 0. Another molecule may be present on their surface, protein D (Rh factor). In its presence, the blood group is Rh positive, in the absence – Rh negative. 85% of white people have Rh positive blood type.
For women planning to become pregnant, it is especially important to know whether the blood group is Rh positive or Rh negative. Why? The Rh factor becomes the cause of problems if Rh negative blood is mixed with Rh positive blood (e.g. during childbirth, miscarriage, incorrectly matched blood). Rh negative organism recognizes the Rh protein on blood cells as a foreign molecule and begins to produce antibodies against it which by attacking them destroy the cells it is on (erythrocytes). The process of making antibodies to the Rh factor is called sensitization.
When the blood of the Rh negative mother comes into contact with the blood of the Rh negative mother, the woman’s body begins to produce antibodies. However, the process of their formation lasts from several days to several weeks. So if the blood of mother and baby comes into contact during labor, the antibodies produced will not attack the blood cells of the newborn baby. However, these antibodies may persist in a woman’s blood until her next pregnancy. It is during its duration that a serological conflict may arise. Antibodies circulating in the body of women are dangerous to the developing fetus as they can cross the placenta and attack the baby’s blood cells, leading to haemolytic disease in the newborn. That is why it is so important to prevent sensitization of Rh negative organism after childbirth or miscarriage.
Prevention of serological conflict
If a Rh negative woman gave birth to a Rh positive child and did not develop anti-Rh antibodies (also known as anti-D antibodies), she should receive a prophylactic dose of anti-D immunoglobulin within 72 hours of delivery. This procedure is ordered by a doctor.
When to do the test?
After your pregnancy is diagnosed, your doctor will ask you to measure your blood type along with the Rh factor. Around the 12th week of pregnancy, every woman (regardless of blood type and Rh factor) should be tested for anti-Rh antibodies.
– if the test at the 12th week of pregnancy does not reveal the presence of anti-Rh antibodies, the test should be repeated between the 28th and 30th week of pregnancy;
– if, however, the test carried out in the 12th week of pregnancy shows the presence of anti-Rh antibodies, it is necessary to determine their type and exact level (the test carried out at the 12th week only answers the question whether the antibodies are present or not). Then, the examination should be repeated according to the doctor’s recommendations (usually every 4 weeks).
The mere detection of immune antibodies in a pregnant woman also means that there is a serological conflict with the fetus. There may be a small amount of anti-Rh antibodies in the blood (which is why their levels are checked several times during pregnancy), which does not pose a threat to the baby.
How is the test performed?
The test involves taking a sample of venous blood (usually from your hand). This is the same as when taking blood for a complete blood count. After collecting the blood, the nurse should give you a cotton ball or gauze to press on the place where the needle has been inserted. If blood was drawn from the veins in the area of the elbow, remember not to bend the arm at the elbow joint for at least 5 minutes after blood collection! This will reduce the risk of a hematoma or bruise where the needle is inserted. If blood is drawn from a pregnant woman, blood can be taken from the child’s father at the same time.
What should we remember?
No special preparation is necessary before blood sampling, and you do not need to be on an empty stomach.
However, be sure to inform the doctor who will order you this test:
– about previous pregnancies, miscarriages,
– if you have had a serological conflict before,
– have you taken preventive anti-D immunoglobulin before,
– if you are prone to bleeding, you suffer from a hemorrhagic diathesis,
– if you have ever had blood transfused,
– what blood group is the child’s father.
After the examination, you can return to your daily activities.