What is Bilirubin?
Bilirubin is a yellow pigment created when red blood cells break down—a normal process that becomes dangerous if a newborn's body can't eliminate it fast enough.
Why It Matters in Newborns
All babies have higher red blood cell turnover than adults
Immature livers struggle to process bilirubin efficiently
When levels rise too high (hyperbilirubinemia), it can cross into the brain, causing kernicterus
The Bilirubin Process
Production: Old red blood cells → Unconjugated bilirubin (fat-soluble)
Liver Processing: Converts to water-soluble form for excretion
Elimination: Leaves body through stool (giving newborns' poop that mustard-yellow color)
Danger Signs
Healthy Range: <5 mg/dL in first 24 hours
Warning Zone:
12 mg/dL at 48 hours
15 mg/dL at 72 hours
Emergency: >25 mg/dL risks brain damage
Key Facts Parents Should Know
✔ Visible jaundice starts at levels >5-7 mg/dL
✔ Feeding frequency directly impacts bilirubin clearance
✔ Blood type incompatibilities (like Rh or ABO) can cause rapid spikes
When to Act:
Yellow skin below the knees
Poor feeding + sleepiness
Dark urine/pale stools
Simple blood tests or skin scanners measure levels accurately. Catching rising bilirubin early allows lifesaving phototherapybefore harm occurs.