Understanding Hemolytic Disease Risk For Newborns And Mothers

Hemolytic disease of the newborn (HDN) is a blood disorder that occurs when a mother's antibodies attack her baby's red blood cells, causing them to break down too early. This can lead to a range of complications, from mild to very severe, including anaemia, jaundice, hepatosplenomegaly, and in severe cases, hydrops fetalis or hyperbilirubinemia and kernicterus in the newborn. The disease typically occurs when there is a blood type mismatch between the mother and baby, with Rh incompatibility being the most common cause. It is relatively uncommon in the United States, with approximately 4,000 cases per year, but it is more likely to occur in subsequent pregnancies and is more prevalent among Caucasian babies. While HDN can be fatal, it is preventable and treatable through early detection, medication, and procedures such as intrauterine blood transfusions and exchange transfusions.

Rh incompatibility

During pregnancy, a small amount of blood from the fetus can mix with the mother's blood during labour and delivery, or through events like vaginal bleeding, injury to the abdomen, miscarriage, or certain prenatal tests. If the mother's blood comes into contact with the fetus's Rh-positive blood, her immune system will treat the foreign Rh-positive fetal cells as a threat, producing antibodies against them. These antibodies can then cross back through the placenta and attack the fetus's red blood cells, causing hemolytic disease of the newborn, or Rh disease. This condition can range from mild to severe, and in rare cases, it can be fatal.

ABO incompatibility

In most cases, ABO incompatibility is not severe. However, in rare cases, it can lead to severe complications for the fetus or newborn, including anemia, jaundice, and hydrops fetalis. The severity of HDN depends on the degree of anemia caused by the underlying incompatibility. Generally, Rh incompatibility results in a more severe form of HDN than ABO-induced HDN.

The risk of ABO incompatibility can be assessed through prenatal testing, which involves determining the mother's blood type and screening for antibodies. If incompatibility is detected, further evaluation through imaging studies may be performed. Treatment options for HDN caused by ABO incompatibility range from phototherapy and supplementation to transfusions in severe cases.

It is important to note that routine antenatal antibody screening blood tests do not screen for ABO HDN. If IgG anti-A or IgG anti-B antibodies are found in the pregnant woman's blood, they are typically not reported because they do not always lead to HDN. Diagnosis of ABO HDN is usually made by investigating a newborn who has developed jaundice during the first week of life.

HDN symptoms during pregnancy

Hemolytic disease of the newborn (HDN) is a blood disorder that occurs when there is an incompatibility between the blood types of a mother and her baby. Although HDN usually does not present any noticeable symptoms during pregnancy, healthcare providers may be able to detect the condition during prenatal tests.

Some symptoms that may be observed during prenatal tests include:

• Yellowing of the amniotic fluid, which may be caused by bilirubin—a substance that forms when red blood cells break down.
• An enlarged liver, spleen, or heart in the baby, or extra fluid in the baby's stomach, lungs, or scalp. These are signs of hydrops fetalis, a severe condition that causes swelling (edema) and can lead to heart failure.

During pregnancy, mild anemia may be observed in the baby, indicating a low red blood cell count. This can make it difficult for the baby's blood to carry enough oxygen from the lungs to other organs and tissues.

In more severe cases, the baby's body may try to compensate for the low red blood cell count by producing more red blood cells in the liver and spleen. This rapid production of new red blood cells can cause these organs to swell, and the immature red blood cells may not function properly, leading to severe anemia.

Another possible complication during pregnancy is hydrops fetalis, which occurs when the baby's body cannot regulate the anemia. This can lead to heart failure and severe fluid buildup in the baby's organs and tissues.

Although HDN typically does not exhibit noticeable symptoms during pregnancy, early detection and treatment are crucial to prevent more severe complications and ensure the best possible outcome for both mother and baby.

HDN symptoms after birth

Hemolytic disease of the newborn (HDN) is a blood disorder that occurs when the blood types of a mother and baby are incompatible. This incompatibility causes the mother's immune system to see the baby's red blood cells as foreign, leading to the development of antibodies that attack and break down the baby's red blood cells.

Jaundice

The breakdown of red blood cells results in elevated levels of bilirubin, a brownish-yellow substance. The newborn's skin, eyes, and umbilical cord may turn yellow due to this excess bilirubin. Jaundice typically appears within 24 to 36 hours after birth and can worsen quickly.

Enlarged Liver and Spleen

The baby's body responds to the breakdown of red blood cells by producing new ones in the liver and spleen, causing these organs to enlarge. This enlargement can be detected through physical examination and medical imaging techniques.

Anemia

Anemia is a condition where the red blood cell count is deficient, leading to a reduced ability to carry oxygen throughout the body. This can cause pallor, or pale-looking skin, in the newborn. Anemia can be detected through a complete blood count test.

Kernicterus

In severe cases, the buildup of bilirubin can reach dangerous levels, spilling over into the brain. This condition, known as kernicterus, can lead to permanent brain damage, seizures, deafness, and even death.

Respiratory Distress

Untreated anemia can cause respiratory distress in the newborn. This difficulty in breathing can be a sign of HDN and may require medical intervention.

Severe Swelling (Edema)

HDN can cause hydrops fetalis, resulting in severe swelling throughout the body, including in the tissues surrounding the lungs, heart, and abdominal organs. This condition can lead to heart failure and respiratory failure.

It is important to note that HDN can vary in severity, and some babies may exhibit no symptoms at all. However, prompt diagnosis and treatment are crucial to prevent potential complications and ensure the best possible outcome for the newborn.

HDN treatment options

Hemolytic disease of the newborn (HDN) is a blood disorder that can develop in a fetus or newborn infant. The condition causes the fetus's red blood cells (RBCs) to be destroyed, leading to anemia and, in some cases, death. The intensity of HDN ranges from mild to very severe.

Feeding and Fluids:

Infants with HDN should be fed frequently and given extra fluids to compensate for the loss of RBCs and prevent dehydration.

Light Therapy (Phototherapy):

Special blue lights are used in light therapy to help convert bilirubin, a byproduct of RBC breakdown, into a form that the baby's body can more easily eliminate. This treatment is recommended when cord bilirubin levels are 3 or higher, and it can help prevent severe jaundice and reduce the need for blood transfusions.

Intravenous Immunoglobulin (IVIG):

IVIG is administered to provide antibodies that help protect the baby's red blood cells from destruction. It is used in cases of previous loss, high maternal antibody titers, aggressive antibodies, and when blood transfusion is not an option due to religious reasons. IVIG can reduce the need for exchange transfusion and shorten the duration of phototherapy.

Plasmapheresis:

Plasmapheresis is a procedure that aims to reduce the mother's antibody titer by directly replacing her plasma and physically removing the antibodies. It can be used in combination with IVIG, especially in women who have previously experienced fetal losses or hydropic fetuses due to HDN.

Intrauterine Transfusion (IUT):

IUT involves transfusing blood directly into the fetus's bloodstream. It can be performed either through the intraperitoneal (IPT) or intravenous (IVT) route, with IVT being the preferred method. IUTs are generally done until 35 weeks of pregnancy, as the risks associated with the procedure outweigh the benefits after this point.

Steroids:

Steroids may be administered to the mother before IUTs and early delivery to help mature the fetus's lungs.

Phenobarbital:

Phenobarbital may be given to the mother to aid in the maturation of the fetus's liver and reduce hyperbilirubinemia.

Early Delivery:

Delivery can be induced anytime after the fetus reaches the age of viability, especially in cases of failed IUT or severe HDN.

Rho(D) Immune Globulin (RhIG or RhoGam):

Rhesus-negative mothers carrying a rhesus-positive infant are offered RhIG to prevent sensitization to the D antigen. It binds to the fetal red blood cells with the D antigen, preventing the mother's immune system from producing an immune response and forming anti-D antibodies.

Exchange Transfusion:

In severe cases of HDN, an exchange transfusion may be necessary. This involves removing a large amount of the baby's blood, including the excess bilirubin and antibodies, and replacing it with fresh donor blood.

Simple Transfusion:

A simple blood transfusion without exchange may be performed and may need to be repeated after the baby is discharged from the hospital.

Temperature Stabilization and Monitoring:

Temperature stabilization and careful monitoring are crucial in the management of HDN to prevent further stress on the newborn's body.

Sodium Bicarbonate:

Sodium bicarbonate may be administered to correct acidosis, a potential complication of HDN.

Assisted Ventilation:

In cases of respiratory distress or failure, assisted ventilation may be required to support the baby's breathing.

Frequently asked questions