What is Hemolytic Disease of the Newborn (HDN)?

From the Guidelines

Hemolytic disease of the newborn (HDN) is a condition that occurs when there is an incompatibility between the blood types of the mother and the baby, leading to the breakdown of the baby's red blood cells 1.

Key Aspects of HDN

• Definition: HDN is caused by the transfer of maternal antibodies against the baby's red blood cells, leading to their destruction.
• Causes: The most common cause of HDN is Rh incompatibility, but it can also be caused by other blood group incompatibilities, such as Kell or c 1.
• Symptoms: Newborns with HDN may exhibit jaundice, anemia, and other complications, including neonatal cholestasis with elevated levels of conjugated bilirubin 1.

Management of HDN

To manage HDN, the following steps are recommended:

• Prenatal monitoring: Pregnant women with a history of HDN or those who are Rh-negative should be closely monitored for signs of fetal anemia 1.
• Rh immune globulin: Rh-negative women should receive Rh immune globulin (RhoGAM) at 28 weeks of gestation and within 72 hours of delivery to prevent the formation of antibodies against the baby's red blood cells 1.
• Phototherapy: Newborns with HDN may require phototherapy to help break down bilirubin, a byproduct of red blood cell breakdown 1.
• Exchange transfusion: In severe cases of HDN, an exchange transfusion may be necessary to replace the baby's blood with donor blood 1.
• Monitoring: Newborns with HDN should be closely monitored for signs of anemia, jaundice, and other complications 1. In terms of medication, Rh immune globulin (RhoGAM) is typically administered at a dose of 300 mcg at 28 weeks of gestation and within 72 hours of delivery 1. The dose may be repeated if the mother has a significant bleed or if the baby's condition worsens.

Outcomes

The outcomes for neonates with HDN can vary, but with proper management, the survival rate is close to 90% 1. However, some newborns may experience long-term complications, such as neurodevelopmental impairment, which can occur in up to 4.8% of cases 1.

From the FDA Drug Label

Rh hemolytic disease of the newborn is the result of the active immunization of an Rho(D) negative mother by Rho(D) positive red cells entering the maternal circulation during a previous delivery, abortion, amniocentesis, abdominal trauma, or as a result of red cell transfusion.

Hemolytic Disease of the Newborn (HDN) is a condition that occurs when an Rho(D) negative mother is immunized by Rho(D) positive red cells entering her circulation, typically during a previous delivery, abortion, amniocentesis, abdominal trauma, or red cell transfusion 2.

From the Research

Definition and Overview of Hemolytic Disease of the Newborn (HDN)

• Hemolytic disease of the newborn (HDN), also known as Erythroblastosis fetalis, is a hemolytic condition that affects fetuses and infants due to maternal-fetal blood group incompatibility 3.
• The condition occurs when maternal antibodies attack fetal red blood cells following alloimmunization due to Rh or ABO incompatibility between the maternal and fetal blood 3, 4.

Causes and Risk Factors

• Maternal-fetal ABO incompatibility is a common cause of HDN, with the incidence ranging from 1 in 150 births to 1 in 3000 births, depending on the degree of anemia and level of serum bilirubin 4.
• HDN can also be caused by Rh incompatibility, with Rh-negative mothers being at risk of developing antibodies against Rh-positive fetuses 3, 5.
• Other risk factors for severe HDN include high levels of IgG anti-A, B, or Kell antibodies in the mother, African ancestry, and previous history of isoimmunized pregnancy 6, 5.

Diagnosis and Management

• Diagnosis of HDN involves extensive history taking, physical examination, serological studies, and imaging modalities such as pelvic ultrasound scans 3.
• Management of HDN includes immunoprophylactic therapies, such as anti-D immunoglobulin, to prevent maternal sensitization and reduce the risk of HDN in subsequent pregnancies 3, 5.
• In cases of severe HDN, treatment may involve phototherapy, exchange transfusions, and other interventions to reduce bilirubin levels and prevent organ dysfunction 4, 6, 7.

Prevention and Treatment

• Delayed cord clamping at birth may be a safe and effective strategy to reduce the risk of HDN and decrease the need for exchange transfusions 7.
• Intravenous immunoglobulin (IVIG) and plasma exchange may also be used to treat HDN, although their application is limited 5.
• Early diagnosis and treatment of HDN are crucial to prevent long-term complications and improve outcomes for affected infants 3, 6.