Neonatal jaundice
Newborns generate more bilirubin and clear it less efficiently than adults, so mild jaundice after the first day is usually physiological, but the timing and conjugation status of the bilirubin are what separate this from pathology capable of crossing into the brain.
In a nutshell
Newborns produce bilirubin faster and clear it slower than adults, so mild jaundice from day 2 onward is usually physiological. Jaundice within the first 24 hours is always pathological (haemolysis, sepsis) and must be investigated urgently. Only unconjugated bilirubin threatens the brain (kernicterus); conjugated jaundice signals hepatobiliary obstruction such as biliary atresia. Phototherapy converts unconjugated bilirubin into an excretable form without needing hepatic conjugation.
Classic presentation
A term infant develops visible jaundice on day 2–3 of life, otherwise well and feeding, with bilirubin below the treatment threshold, resolving by two weeks.
Key points
- Jaundice in the first 24 hours of life is never physiological: think haemolysis (rhesus/ABO incompatibility), sepsis or congenital infection.
Educational content pending clinical review. Not medical advice.