How does rhogam prevent erythroblastosis fetalis

Incompatibilities of ABO blood types do not cause erythroblastosis fetalis. Fetal red blood cells RBCs normally move across the placenta to the maternal circulation throughout pregnancy. Movement is greatest at delivery or termination of pregnancy. Movement of large volumes eg, 10 to mL is considered significant fetomaternal hemorrhage; it can occur after trauma and sometimes after delivery or termination of pregnancy.

In women who have Rh-negative blood and who are carrying a fetus with Rh-positive blood, fetal RBCs stimulate maternal antibody production against the Rh antigens. The larger the fetomaternal hemorrhage, the more antibodies produced. The mechanism is the same when other antigen systems are involved; however, Kell antibody incompatibility also directly suppresses RBC production in bone marrow.

Other causes of maternal anti-Rh antibody production include injection with needles contaminated with Rh-positive blood and inadvertent transfusion of Rh-positive blood. No complications develop during the initial sensitizing pregnancy; however, in subsequent pregnancies, maternal antibodies cross the placenta and lyse fetal RBCs, causing anemia, hypoalbuminemia, and possibly high-output heart failure or fetal death. Anemia stimulates fetal bone marrow to produce and release immature RBCs erythroblasts into fetal peripheral circulation erythroblastosis fetalis.

Hemolysis results in elevated indirect bilirubin levels in neonates, causing kernicterus Kernicterus Kernicterus is brain damage caused by unconjugated bilirubin deposition in basal ganglia and brain stem nuclei. Normally, bilirubin bound to serum albumin stays in the intravascular space. Usually, isoimmunization does not cause symptoms in pregnant women.

Serial antibody level measurements and middle cerebral artery blood flow measurements for pregnancies considered at risk. At the first prenatal visit, all women are screened for blood type, Rh type, and anti-Rho D and other antibodies that are formed in response to antigens and that can cause erythroblastosis fetalis reflex antibody screening. If he has Rh-negative blood and is negative for the antigen corresponding to the antibody identified in the mother, no further testing is necessary. If he has Rh-positive blood or has the antigen, maternal anti-Rh antibody titers are measured.

If titers are positive but less than a laboratory-specific critical value usually to , they are measured every 2 to 4 weeks after 20 weeks. If the critical value is exceeded, fetal middle cerebral artery MCA blood flow is measured at intervals of 1 to 2 weeks depending on the initial blood flow result and patient history; the purpose is to detect high-output heart failure, indicating high risk of anemia.

Elevated blood flow for gestational age should prompt consideration of percutaneous umbilical blood sampling and intrauterine blood transfusion. If fetal blood is Rh positive or status is unknown and if MCA blood flow is elevated, fetal anemia is likely.

When Rho D status is uncertain, noninvasive cell-free fetal DNA screening Cell-free fetal nucleic acid testing Genetic evaluation is part of routine prenatal care and is ideally done before conception. The extent of genetic evaluation a woman chooses is related to how the woman weighs factors such as This test is available in North America.

The clinical features of erythroblastosis fetalis result from destruction of fetal RBCs by maternal antibodies against them. They can range from mild anemia and jaundice to fetal death in utero. In another scenario, the baby may develop jaundice after birth, in spite of the fact that there is no Rh incompatibility. Under these circumstances, the symptoms can be attributed to ABO incompatibility. However, the symptoms are much milder than in case of Rh incompatibility. Doppler Ultrasound.

The doctor may recommend a non-invasive test to detect fetal middle cerebral artery blood flow by means of Doppler ultrasound. This procedure is used to sample the amniotic fluid that surrounds the developing fetus inside the uterus. A needle is inserted into the amnion the sack filled with amniotic fluid using ultrasound guidance to take a fluid sample. Moreover, analysis of the amniotic fluid can measure the bilirubin concentration to predict the severity of the disease.

After birth, the baby may need to be given further blood transfusions. Fluids may be administered intravenously to increase low blood pressure. Mechanical respiratory support may need to be provided to treat respiratory insufficiency. Some specific strategies that may be adopted are briefly highlighted below:.

Erythroblastosis fetalis can be prevented by carrying out screening tests and by the administration of Rh factor immunoglobulins to the pregnant mother. These aspects are briefly discussed below:. Follow Medindia. By using our site, you acknowledge that you have read and understand our Cookie Policy , Privacy Policy , and our Terms of Use.

Ask your question. What is Erythroblastosis Fetalis? What are the Causes of Erythroblastosis Fetalis? As the antibodies destroy the cells, the baby gets sick. This is called erythroblastosis fetalis during pregnancy. This can happen in a past pregnancy with an Rh positive baby. Or it can happen because of an injury or test in this pregnancy with an Rh positive baby.

During pregnancy, you won't notice any symptoms. But your healthcare provider may see the following during a prenatal test:.

A yellow coloring of amniotic fluid. This color may be because of bilirubin. This is a substance that forms as blood cells break down. Your baby may have a big liver, spleen, or heart.

There may also be extra fluid in their stomach, lungs, or scalp. These are signs of hydrops fetalis. This condition causes severe swelling edema. Your baby may not look yellow right after birth.

But jaundice can come on quickly. It often starts in 24 to 36 hours. A newborn with hydrops fetalis may have severe swelling of their entire body.

They may also be very pale and have trouble breathing. HDN can cause symptoms similar to those caused by other conditions. Sometimes this diagnosis is made during pregnancy. It will be based on results from the following tests:. Blood test.

Testing is done to look for Rh positive antibodies in your blood. This test can show enlarged organs or fluid buildup in your baby.

This test is done to check the amount of bilirubin in the amniotic fluid. In this test, a needle is put into your abdominal and uterine wall. It goes through to the amniotic sac. The needle takes a sample of amniotic fluid. Percutaneous umbilical cord blood sampling.

This test is also called fetal blood sampling. This is done to check if your baby needs an intrauterine blood transfusion. Testing of your baby's umbilical cord.

This test puts red blood cells into your baby's circulation. In this test, a needle is placed through your uterus. Your baby may need sedative medicine to keep him or her from moving. You may need to have more than 1 transfusion. If your baby gets certain complications, they may need to be born early.

Your healthcare provider may induce labor may once your baby has mature lungs. This can keep HDN from getting worse. In this test, your baby is put under a special light. This helps your baby get rid of extra bilirubin. Your baby may need oxygen, a substance in the lungs that helps keep the tiny air sacs open surfactant , or a mechanical breathing machine ventilator to breathe better. It replaces it with fresh blood that has a normal bilirubin level.

It also lowers their bilirubin level. In this test, your baby will alternate giving and getting small amounts of blood.