What is the meaning of rh hemolysis

To put it simply, Rh hemolysis means that if the mother is Rh-negative and the father is Rh-positive, then generally speaking, there is a high chance that the children will be RH-positive. During this period, the baby's chance of suffering from Rh hemolysis is 10%. If a newborn has Rh hemolysis, it can easily cause fetal death, but it will not affect the mother's health.

Neonatal RH hemolytic disease is a hemolytic disease caused by the immune antibody IgG in the maternal blood entering the fetal blood circulation through the placenta, causing an immune response and causing fetal red blood cell destruction.

If left untreated, most severely affected fetuses will die. Rheumatoid arthritis can also cause jaundice (yellowing of the skin and eyes), anemia, brain damage, heart failure, and even death in newborns, but it will not affect the mother's health.

In the United States, approximately 20,000 babies are born with Rhesus hemolytic disease each year. However, since the advent of treatment for Rhesus hemolytic disease in 1968, the number of newborns with Rhesus hemolytic disease has dropped significantly. However, not all pregnant women who need preventive treatment can receive it, so there is still a small number of pregnant women who cannot benefit from this technology. As a result, approximately 4,000 babies are still born each year with Rhesus hemolytic disease.

How to prevent RH hemolysis?

To prevent RH hemolytic disease, all children of women with RH negative blood type should have an RH blood type test at birth.

All Rh-negative mothers who are pregnant with an Rh-positive child should be given a pure-blood Rh immune globulin injection 72 hours after delivery, which can prevent more than 95% of sensitization in Rh-negative women.

However, some studies show that about 2% of pregnant women are sensitized before giving birth. Therefore, in order to prevent early sensitization, RH immunoglobulin can be injected into pregnant women at 28 weeks of pregnancy and after delivery.

Women with RH negative blood type should be injected with RH immune globulin after spontaneous abortion, ectopic pregnancy, artificial abortion or transfusion of RH positive blood. In addition, RH immune globulin should be injected after amniocentesis and fetal chorionic villus sampling.

What is the cause of RH hemolysis?

Because the fetal red blood cells entering the mother's body are quickly neutralized by ABO antibodies and have no time to produce RH antibodies, RH hemolytic disease is not likely to occur, and even if it does occur, the condition is relatively mild. Douohoe et al. (1964) found that the neutralizing power of mother-child AO incompatibility (mother O, child A) is stronger than that of mother-child BO (mother O, child B). The former can protect 90% of women from allergies, while the latter can only protect 55% of women from allergies.

Most people in the group have RH positive blood type and have RH antigen, which is a genetic protein on the surface of red blood cells. About 15% of Caucasians and 7% of African Americans in the United States do not have RH antigen, that is, they have RH negative blood type. People with RH negative blood type will not have any health problems themselves, but if a woman has RH negative blood type, there is a risk of giving birth to a baby with RH hemolytic disease.

The offspring of a mother with RH negative blood type and a father with RH positive blood type are likely to inherit the father's RH positive blood type and be in danger at birth, especially during delivery, when some RH positive red blood cells of the fetus may enter the mother's blood. These fetal red blood cells with RH antigens are foreign to the mother's body. The mother's body tries to reject these foreign substances by producing anti-RH antibodies. This initiated maternal immune response is called sensitization.

During a first pregnancy, there is little risk to an RH-positive fetus because the child is usually born before the mother becomes sensitized, or at least before she produces adequate amounts of RH antibodies. However, once sensitization occurs, the mother will continue to produce RH antibodies as part of her blood throughout her life. In each subsequent pregnancy, the mother's RH antibodies will be able to pass through the placenta to reach the fetus, so with each subsequent pregnancy, the risk of the child developing severe RH hemolytic disease increases.

If the fetus has RH positive blood type, the mother's RH antibodies will destroy the fetus's red blood cells, causing RH hemolytic disease in the baby.