Introduction
The etiology of hemolytic disease of the newborn (HDN), which results from Rhesus (Rh) isoimmunization, is the transplacental channeling of maternal antibodies active against the infant's paternal Rh antigens. Hemolysis can result in anemia during the intrauterine phase, and after birth, it can cause jaundice and anemia of varying degrees. Some newborns who show little or no symptoms at first can later develop late-onset anemia.
What Is Rh-Isoimmunization?
An Rh-negative mother's development of antibodies against the paternal Rh antigen on fetal red blood cells is known as Rh isoimmunization, an illness that can be avoided. Fetomaternal hemorrhage due to a prior pregnancy, abortion, trauma, or invasive procedure exposes the fetal blood to the mother's circulation, leading to the generation of these antibodies. This process, known as sensitization or iso/alloimmunization, is more common in the first pregnancy of a Rh-negative woman but becomes less common in future pregnancies.
The firstborn child is typically unaffected by sensitization, but subsequent babies may develop hemolytic illness. Anti-D immunoglobulin, which counteracts the effects of these antibodies, can be given prophylactically to prevent isoimmunization in pregnant Rh-negative women. In HDN, which is typically treated with phototherapy and exchange transfusion, fetal RBCs can be destroyed due to a failure or delay in prophylaxis. For many years, Rh isoimmunization was the primary cause of sickness and mortality among newborns and young children; however, with the development of anti-D immunoglobulin prophylaxis, this rate was significantly decreased.
What Is the Rh Factor?
One protein found on the exterior or surface of the red blood cells is called the Rh factor, also known as the Rhesus factor. The Rh factor is inherited from one's biological parents if the protein is inherited. Being Rh-positive means having the protein. One is Rh-negative if they lack the protein. Rh-positive individuals make up the majority, or around 85 percent.
Complications may arise during pregnancy if the fetus is Rh-positive and one is Rh-negative. It is referred to as Rh factor incompatibility. There are ways to avoid the consequences of Rh incompatibility.
Which Are the Typical Blood Types?
A person's blood type is determined by the protein found on the surface of red blood cells. Additionally, each blood type includes a positive or negative component. The Rh factor is shown by the positive or negative next to the blood type. There are no issues or negative effects related to the Rh factor on health. It only becomes significant when blood types are mixed, such as childbirth or pregnancy.
The most prevalent blood kinds are:
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O Positive.
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O Negative.
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A Positive.
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A Negative.
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B Positive.
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B Negative.
What Disorders Are Associated With Rh-Isoimmunization?
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Neonatal anemia is caused by Rh isoimmunization and can range in severity from mild to severe anemia in the first postnatal period to fetal hydrops in pregnancy.
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Fetal RBCs may continue to be destroyed by these isoantibodies for six to ten weeks after birth.
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The ongoing damage could be either a gradual improvement in reticuloendothelial function in the second week of life or a lack of exchange transfusion in the early postnatal period.
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Due to the liver's parallel maturation, there may not always be a correlation between this increased rate of hemolysis and a rise in serum bilirubin content.
What Are the Signs and Symptoms of Rh-Immunization?
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The infant may experience minor to dangerous symptoms from isoimmunization, while the mother will not experience any symptoms.
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When an incompatibility is even moderate, it destroys red blood cells without causing other problems.
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The infant may become extremely feeble and, in extreme circumstances, may pass away if the process is severe enough.
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Following birth, the infant will have poor muscular tone (hypotonia), be lethargic, and have yellow skin and eye whites (jaundice).
How Is Rh-Immunization Diagnosed?
A few tests can be used during prenatal visits to identify women who may be at risk for isoimmunization.
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Blood type.
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Rh type.
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Antibody Screening Tests: The screening test for Rh antibodies is a blood test that looks for Rh antibodies in the blood. If one has Rh-negative blood and has been exposed to Rh-positive blood, the immune system may produce antibodies to fight Rh-positive blood. When a pregnant woman possesses these antibodies, it is known as Rh sensitization.
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Amniocentesis: Occasionally, amniocentesis is used to diagnose the specific incompatibility before delivery. Prenatal RhD typing of the fetus in cases of Rhesus incompatibility necessitates intrauterine blood collection via cordocentesis or chorionic villus biopsy. Amniocentesis is less likely to boost maternal immunization and is a simpler procedure.
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Ultrasonography: If isoimmunization is found, ultrasonography tracks the severity of the baby's anemia.
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In addition, after delivery, the baby's blood may show indications of red blood cell degeneration and higher-than-normal bilirubin levels from umbilical cord blood samples.
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A positive result on the Coombs blood test.
How Can Rh-Immunization Be Treated?
One of the two alternatives below can be used if the baby's anemia is severe.
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Phototherapy.
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Exchange transfusion.
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When the baby is old enough to be born safely, the neonatologists take charge of getting him or her into the intensive care nursery, where they administer transfusions and other treatments.
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Red blood cells are transfused to a premature newborn by sewing a needle into its umbilical cord and giving it red blood cells before it is born if the baby is too early to be delivered safely.
How Can Rh-Immunization Be Prevented?
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RhoGAM (Rh-immune globulin) can be administered to the pregnant or recently delivered mother if it is determined that she has a Rh-negative blood type.
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Prenatal anti-D immunoglobulin administration can prevent Rh-negative pregnant women from becoming isoimmunized by counteracting the effects of isoantibodies.
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Failure or delay in prophylaxis might harm fetal red blood cells (RBCs), which can result in hemolytic disease of the newborn (HDN).
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Exchange transfusion and phototherapy are the standard treatments for HDN.
Conclusion
A disorder that develops when a pregnant woman's immune system reacts to her unborn child's blood cells, destroying them since her blood protein is incompatible with the unborn child's. When a mother who is Rh-negative generates antibodies against the paternal Rh antigen on fetal red blood cells, it is known as Rh isoimmunization, a disorder that can be prevented. Because of fetomaternal bleeding originating from a prior pregnancy, abortion, trauma, or invasive procedure, the fetal blood is exposed to the mother's circulation, generating these antibodies.
