• Clinical science

Neonatal jaundice (Icterus neonatorum)


Neonatal jaundice is one of the most common conditions occurring in newborn infants and is characterized by elevated levels of bilirubin in the blood (total serum bilirubin concentration > 5 mg/dL or > 85.5 γmol/L). The most common cause of neonatal jaundice is a physiological rise in unconjugated bilirubin, which results from hemolysis of fetal hemoglobin and an immature hepatic metabolism of bilirubin. Physiological jaundice is harmless and occurs in most infants between the second and the eighth day of life. Pathologic neonatal jaundice can be conjugated or unconjugated and is typically a symptom of an underlying disease. Possible conditions include hemolytic anemias, blood group incompatibilities, Gilbert and Crigler–Najjar syndromes, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and congenital biliary flow obstructions. Hyperbilirubinemia can cause drowsiness and poor feeding in the newborn, and in severe cases, unconjugated bilirubin can cross the blood-brain barrier and cause permanent neurological damage (kernicterus). The degree of hyperbilirubinemia can be measured by transcutaneous and/or serum bilirubin measurements. Treatment modalities include phototherapy, intravenous immune globulin (IVIG), and exchange transfusion, in addition to specific therapies for the respective underlying conditions. Treatment is targeted at reducing the risk of kernicterus and hence permanent neurological sequelae.


Physiological neonatal jaundice Pathological neonatal jaundice

Etiology of conjugated hyperbilirubinemia

Etiology of unconjugated hyperbilirubinemia



Physiological hyperbilirubinemia

Pathological hyperbilirubinemia

  • Can be caused by multiple mechanisms:

Subtypes and variants

Breastfeeding jaundice

  • Pathophysiology: insufficient breast milk intake; → lack of calories and inadequate quantities of bowel movements to remove bilirubin from the body → ↑ enterohepatic circulationincreased reabsorption of bilirubin from the intestinesunconjugated hyperbilirubinemia
  • Clinical features: onset within 1 week
  • Treatment: increase breastfeeding sessions, rehydration

Breast milk jaundice


Clinical features



  1. Physical examination for icterus
  2. Bilirubin tests
  3. Other laboratory tests

Physiological neonatal jaundice is a diagnosis of exclusion! Laboratory tests should first rule out all pathological causes of neonatal jaundice!

Jaundice in a term newborn less than 24 hours old is always pathologic!




Phototherapy is the primary treatment in neonates with unconjugated hyperbilirubinemia.

Exchange transfusion

  • Most rapid method for lowering serum bilirubin concentrations
  • Indications
    • Threshold in a 24-hour-old term baby is a total serum bilirubin value > 20 mg/dL
    • Inadequate response to phototherapy, or a rapid rise in the total serum bilirubin level (> 1 mg/dL/hour in less than 6 hours)
    • Acute bilirubin encephalopathy
    • Hemolytic disease, severe anemia
  • Implementation
  • Side effects: higher mortality and morbidity from infections, acidosis, thrombosis, hypotension, and electrolyte imbalances

IV immunoglobulin

  • Used in cases with immunologically mediated conditions, or in the presence of Rh, ABO, or other blood group incompatibilities that cause significant neonatal jaundice
  • Dose range for IVIG: 500–1000 mg/kg



  • Favorable in most cases
  • In rare cases kernicterus may occur, resulting in permanent neurological sequelae.


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last updated 06/12/2020
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