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Fetal erythroblastosis
Last reviewed: 23.04.2024
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Fetal erythroblastosis is a hemolytic anemia in a fetus or newborn caused by transplacental transmission of maternal antibodies to fetal erythrocytes. The disorder is usually the result of incompatibility between blood groups of the mother and fetus, often Rh0 (D) antigen. Diagnosis begins with prenatal screening of mother antigens and antibodies, a father survey, a series of mother antibody titer measurements, and fetal testing may also be required. Treatment should include intrauterine transfusion in the fetus or exchange transfusion in the newborn. In order to prevent Rh0 (D), women at risk are injected with an immunoglobulin.
[Causes Fetal erythroblastosis
What causes fetal erythroblastosis?
Traditionally, fetal erythroblastosis is the result of Rh0 (D) incompatibility, which can develop when a woman with Rh-negative blood is fertilized by a man with Rh-positive blood and a fetus with Rh-positive blood is formed. Other factors of maternal and fetal incompatibility that can cause fetal erythroblastosis include Kell, Duffy, Kidd, MNSs, Luteran, Diego, Xg, P, Ee and Cc and other antigenic systems. Incompatibility of blood groups by type ABO does not cause fetal erythroblastosis.
Erythrocytes of the fetus penetrate the placenta into the bloodstream of the mother during the entire pregnancy. Movement is greatest during labor or termination of pregnancy; with a trauma of the abdominal cavity of the mother, maternal hemorrhage can be noted. In women who have Rh-negative blood and carry a fetus with Rh-positive blood, the fetal erythrocytes stimulate production of antibodies against Rh-antigens in the mother (isoimmunization); when other antigen systems are involved, the mechanism is the same.
In subsequent pregnancies, the mother's antibodies penetrate the placenta and destroy the red blood cells of the fetus, causing anemia, hypoalbuminemia and, possibly, hypersystolic heart failure or intrauterine death.
Anemia stimulates the fetal bone marrow to produce and release immature erythrocytes (erythroblasts) into the peripheral blood circulation of the fetus (fetal erythroblastosis). Hemolysis leads to an increase in the level of bilirubin in a newborn, which is the cause of bilirubin encephalopathy in newborns. Isoimmunization in pregnant women is usually asymptomatic.
Diagnostics Fetal erythroblastosis
Diagnosis of fetal erythroblastosis
At the first prenatal visit, all women take a blood test for Rh-belonging. If a woman has Rh-negative blood, then determine the father's blood accessory and her zygote (if paternity is determined). If the blood is Rh-positive, then the titre of Rh-antibodies in the mother is measured at 2628 weeks. If the positive titers are only in dilution less than 1:32 (or below the critical values of the local blood bank and plasma), then titles are measured more often. If the titers are about 1:32 (or above the critical values of the local laboratory), the average blood flow in the cerebral artery of the fetus is measured at intervals of 12 weeks, depending on the titers and the patient's anamnesis; the goal is to detect heart failure. With increased blood flow for gestational age, it is necessary to produce a percutaneous umbilical blood sampling (if anemia is suspected), or every 2 weeks spectrophotometric measurement of bilirubin levels in amniotic fluid obtained by amniocentesis. If paternity is known and the father is probably heterozygous for RhO (D), then the Rh-belonging of the fetus to the cells of the amniotic fluid is determined. If fetal blood is Rh-negative or if the average blood flow in the cerebral artery or bilirubin level in the amniotic fluid remains normal, the pregnancy can continue until the term without treatment. If the fetus Rh-positive blood or Rh-accessory is not determined and if the average blood flow of the cerebral artery or bilirubin levels in the amniotic fluid is increased, then, assuming embryonic anemia, the fetus can be transfused by a specialist in an institution equipped for pregnancy with the presence of risk factors . Transfusions are necessary every 12 weeks, until the maturity of the fetus is reached (usually 3234 weeks) and delivery will not be possible. Before the first transfusion, corticosteroids should be prescribed, with pregnancy of 24 weeks or more.
Treatment Fetal erythroblastosis
Treatment of fetal erythroblastosis
The delivery should be as atraumatic as possible. Manual removal of the placenta should be avoided, because this can cause the fetal cells to enter the mother's circulation. Newborns with erythroblastosis are immediately evaluated by a pediatrician to determine the need for an exchange transfusion.
Prevention
How to prevent fetal erythroblastosis?
Maternal sensitization and production of antibodies due to Rh incompatibility can be prevented by the administration of RhO (D) immunoglobulin. This drug contains high titers of anti-Rh antibodies that neutralize Rh-positive red blood cells of the fetus. Since the intensity of maternal-maternal metabolism and the likelihood of sensitization increase by the end of pregnancy, the preparation is carried out within 72 hours until the completion of any pregnancy, regardless of its termination (delivery, abortion, treatment of ectopic pregnancy). The standard dose of the drug is 300 μg.
The method of immune outlets can be used to exclude significant fetomaternal bleeding, and if the results are positive, then the amount of fetal blood in the mother's bloodstream is determined using the Kleichauer-Betke test (acidic elution). If the maternal hemorrhage is massive (> 30 ml of the whole blood), then additional injections (up to five doses of 300 μg within 24 hours) are necessary. Treatment at the end of pregnancy is sometimes ineffective, because sensitization could begin earlier during pregnancy. Therefore, at approximately 28 weeks, all pregnant women with Rh-negative blood and without previous sensitization data also receive a dose of immunoglobulin. Since the use of RhO (D) immunoglobulin in sensitized women does not have any risks, the injection can be done when blood is taken to measure the titer at 28 weeks. Some experts recommend a second dose if the delivery did not occur on the 40th week. Rh0 (D) immunoglobulin should also be administered after any episode of vaginal bleeding and after amniocentesis or a chorionic villus biopsy. Anti-IL-antibodies persist for more than 3 months after a single dose.