Hemolytic Disease of the Newborn - An Overview

Introduction

Hemolytic disease of the newborn (HDN), also known as erythroblastosis fetalis, is a condition that occurs when the mother and the fetus have incompatible blood types. It occurs when the mother has Rh-negative blood, and the fetus has Rh-positive blood. The mother's immune system may produce antibodies that attack the baby's red blood cells, leading to anemia, jaundice, and other complications.

What Are the Causes of Hemolytic Disease in Newborns?

Incompatibility in the Rh factor of blood in mother and child is the main cause of the disease. Rh factor can be seen on the surface of red blood cells.

• If the mother is Rh-negative and the baby is Rh-positive, the mother's immune system may see the baby's Rh-positive blood cells as foreign and produce antibodies against them.

• If the mother gets pregnant with another Rh-positive baby, her immune system may recognize the Rh-positive blood cells and produce more antibodies against them. These antibodies attack the baby's red blood cells in the placenta, leading to hemolytic disease in the newborn.

What Are the Risk Factors?

Some factors increase the risk of developing HDN, including:

• Being Rh-negative.

• Having a previous pregnancy with an Rh-positive baby.

• Previous blood transfusion or transplant.

• Previous miscarriage or ectopic pregnancy.

• Invasive procedures during pregnancy, such as amniocentesis or chorionic villus sampling.

• Maternal infections, such as rubella, cytomegalovirus, or toxoplasmosis.

What Are the Symptoms?

The symptoms of HDN will be different based on the condition and can include:

• Jaundice: Jaundice is the yellowing of the skin and eyes due to the collection of bilirubin in the blood. Bilirubin is a consequence of the breakdown of hemoglobin in the red blood cells. In HDN, the destruction of red blood cells leads to an increase in bilirubin levels, causing jaundice.

• Anemia: Anemia is a condition in which the level of red blood cells to carry oxygen to the body's tissues is reduced. In HDN, the destruction of red blood cells can lead to anemia, which can cause fatigue, pale skin, and a rapid heartbeat.

• Enlarged Liver and Spleen: The liver and spleen can become enlarged due to the increased workload of processing and removing the destroyed red blood cells.

• Edema: In severe cases of HDN, the baby may develop edema due to the decreased ability of the body to remove excess fluid.

• Fetal Hydrops: Fetal hydrops is a severe form of HDN that occurs when the baby's body cannot compensate for the destruction of red blood cells. It can cause excessive fluid buildup in the body, leading to heart failure, respiratory distress, and other life-threatening complications.

• Kernicterus: It is a rare but serious complication of HDN that occurs when bilirubin levels become too high, leading to brain damage. Symptoms of kernicterus include poor feeding, lethargy, high-pitched crying, and seizures.

The condition must be diagnosed and treated to reduce the complications and ensure the best possible outcome for the baby.

How Is the Disease Diagnosed?

• Prenatal Diagnosis: During pregnancy, the following tests may be performed to diagnose hemolytic disease of the newborn (HDN):

  • Blood Typing: Blood typing is a standard prenatal test that determines the mother's and baby's blood types.

  • Antibody Screening: Antibody screening is a blood test that detects antibodies in the mother's blood.

  • Amniocentesis: Amniocentesis is a procedure in which a small sample of the amniotic fluid is removed from the sac surrounding the baby. The sample can be tested for bilirubin levels, which can indicate the severity of HDN.

• Postnatal Diagnosis: After the baby is born, the following tests may be performed to diagnose HDN:

  • Blood Tests: Blood tests can measure the baby's bilirubin levels and assess the severity of the anemia.

  • Coombs Test: The Coombs test, also known as the direct antiglobulin test (DAT), is a blood test that detects antibodies that are attached to the baby's red blood cells. The antibodies present denotes that the baby has been exposed to the mother's antibodies and may have HDN.

  • Ultrasound: An ultrasound can detect signs of fetal hydrops, such as excessive fluid buildup in the body.

How Is Hemolytic Disease of Newborns Treated?

HDN is a serious condition that requires prompt treatment to manage symptoms and prevent complications. The treatment may vary, corresponding to the severity of the condition, and may involve a combination of therapies. Some common treatments for HDN include:

• Phototherapy: Phototherapy is a common treatment for jaundice in newborns. It involves placing the baby under special lights that help to break down bilirubin in the blood, which can then be excreted through the urine. The baby's skin may turn slightly yellow during phototherapy, but this is a normal and temporary side effect.

• Intravenous Immunoglobulin (IVIG): IVIG is a medication that contains antibodies that can help suppress the mother's immune response and prevent further destruction of the baby's red blood cells. IVIG is given to the mother during pregnancy or directly to the baby after birth.

• Blood Transfusions: It is necessary to replace the baby's damaged red blood cells and improve oxygen delivery to the body's tissues. Blood transfusions may be given during exchange transfusion or as a standalone treatment.

• Exchange Transfusion: Exchange transfusion is a procedure in which the baby's blood is slowly removed and replaced with donor blood. This can help to remove bilirubin and replace damaged red blood cells. Exchange transfusion is typically reserved for severe cases of HDN or when other treatments have failed.

• Fetal Transfusions: In some cases, fetal transfusions may be necessary to treat severe cases of HDN during pregnancy. Fetal transfusions involve injecting donor blood into the baby's umbilical vein, which can help to replace damaged red blood cells and prevent complications.

• Monitoring: Babies with HDN will need to be closely monitored to ensure that their bilirubin levels do not become too high or lead to brain damage as a result of kernicterus. This may involve regular blood tests, physical exams, and monitoring of vital signs.

Conclusion

Proper prenatal screening and prompt postnatal diagnosis are crucial in treating the condition. It is advisable to seek advice from medical professionals to identify the risks of the disease and ensure the well-being of the child.