Diagnosing HDN typically involves a combination of prenatal and postnatal tests to monitor both the mother and the baby.

Antenatal (Before Birth) Diagnosis

• Screening for Risk:

• Blood Group Testing: 
  • Early in pregnancy, both parents’ blood types are tested to check for any potential incompatibility, especially if the mother is Rh-negative.
• Antibody Testing: 
  • The mother’s blood is tested for antibodies that could harm the baby’s red blood cells. These tests are typically done at 12-16 weeks, 28-32 weeks, and 36 weeks of pregnancy.

• Monitoring Fetal Health:

• Ultrasound and Doppler Tests: 
  • If there’s a risk of hemolytic disease, the baby’s condition is monitored using ultrasound and Doppler imaging. 
  • These tests check for signs like an enlarged liver or spleen, fluid buildup (hydrops), and increased blood flow in the baby’s brain, which could indicate anemia.

• Invasive Testing:

• Amniocentesis: 
  • Sometimes, doctors may take a sample of the amniotic fluid (the fluid around the baby) to measure bilirubin levels, which can indicate how much red blood cell breakdown is occurring.
• PUBS (Percutaneous Umbilical Blood Sampling): 
  • This is a procedure where blood is taken directly from the baby’s umbilical cord to check hemoglobin levels and, if necessary, give the baby a blood transfusion while still in the womb.

• Non-Invasive Monitoring:

• Doppler Ultrasound: 
  • This test measures the speed of blood flow in the baby’s brain, which can help detect anemia without needing invasive procedures.

Postnatal (After Birth) Diagnosis

Immediate Testing:

• Cord Blood Testing: 
  • After the baby is born, blood from the umbilical cord is tested for blood type, Rh factor, hemoglobin levels, and the Coombs test, which checks for antibodies that might attack the baby’s red blood cells.
• Positive Coombs Test: 
  • If this test is positive, it means the baby’s red blood cells are being attacked, and additional tests are done to measure bilirubin levels (to assess jaundice) and identify the specific antibodies involved.

• Blood Smear Findings: 
  • A blood smear (a sample of blood looked at under a microscope) may show rounder-than-normal red blood cells called spherocytes, which can sometimes suggest a condition called hereditary spherocytosis.

Other Lab Findings:

• High Bilirubin: Often, the only other abnormal lab result is high bilirubin levels, which can cause jaundice (yellowing of the skin and eyes).
• Hemoglobin Levels: The baby’s hemoglobin levels (which indicate the amount of red blood cells) are usually normal but can be slightly low, around 10-12 g/dL.
• Reticulocytes: The number of young red blood cells (called reticulocytes) may be higher than normal, indicating that the baby’s body is trying to produce more red blood cells to replace the ones being destroyed.

Ongoing Monitoring:

• Bilirubin Levels: Bilirubin is a substance that builds up when red blood cells are broken down. If levels are high, it can lead to jaundice, which needs to be closely monitored to prevent complications like brain damage (kernicterus).

Main Goals of Treatment:

1. Preventing Serious Complications: The primary aim is to prevent severe anemia (low red blood cell levels) and lack of oxygen (hypoxia) in the baby, which can be life-threatening before or after birth.
2. Protecting the Brain: Another crucial goal is to prevent brain damage (neurotoxicity) caused by very high levels of bilirubin, a substance that builds up when red blood cells break down.

• Treatment Before Birth

Before Birth Care:

• Fetal Monitoring: 
  • Doctors use ultrasound to monitor the baby’s condition and determine if an in-utero (before birth) blood transfusion is needed.
• In-Utero Transfusion: 
  • If the baby has severe anemia, doctors may perform a blood transfusion directly into the baby’s umbilical vein. This helps replace the damaged red blood cells.
• Timing of Delivery: 
  • The baby may be delivered early if the lungs are mature, if there are complications, or if the pregnancy reaches 35-37 weeks.

After Birth Care:

• Immediate Care at Birth:
  • A skilled doctor should be present at the birth, and special blood for transfusions should be ready.
  • If the baby shows signs of severe anemia or other complications at birth (such as pale skin, enlarged liver or spleen, or swelling), immediate medical care is essential.
  • This may include 
    • stabilizing the baby’s body temperature
    • correcting any blood chemistry imbalances
    • providing a small blood transfusion if needed. 
    • If the baby has difficulty breathing, assisted ventilation might be necessary.
• Exchange Transfusion:
  • If the baby is at high risk of developing severe anemia or very high bilirubin levels, an exchange transfusion may be needed. 
  • This involves gradually replacing the baby’s blood with donor blood to remove the antibodies and excess bilirubin.

• Intravenous Immunoglobulin (IVIG):
  • Administering IVIG early on can help reduce the breakdown of red blood cells, lower bilirubin levels, and decrease the need for exchange transfusions.
• Phototherapy:
  • Phototherapy is a treatment that uses special lights to help lower high levels of bilirubin in the baby’s blood, which can cause jaundice.

• Some babies with ABO hemolytic disease might develop anemia slowly over a few weeks and could need a blood transfusion later on. After the baby goes home, it’s important to regularly monitor their hemoglobin or hematocrit levels to ensure they stay healthy.

At Gertrude’s Children’s Hospital, we are committed to providing the best possible care for children with Haemolytic Disease of the Newborn (HDN). Here’s why families trust us:

If you are concerned about your baby’s health or have been told your baby may be at risk for Haemolytic Disease of the Newborn, don’t hesitate to reach out to us. Early diagnosis and treatment are crucial for the best outcomes. At Gertrude’s Children’s Hospital, our team is here to provide the expert care and support your family needs.