What is a normal bilirubin range for a newborn?

• A. 3-4 mg/dL
• B. 6-7 mg/dL
• C. 8-9 mg/dL
• D. 5-6 mg/dL

Answer: (D)

Bilirubin in newborns is shaped by how fast it's produced and how well the liver can process it. After birth, newborns have a high rate of red blood cell turnover and an immature liver that isn’t fully efficient at conjugating bilirubin. This leads to a predictable rise in unconjugated bilirubin, known as physiologic jaundice. In healthy term infants, this bilirubin level typically peaks around five to six milligrams per deciliter a few days after birth, then gradually falls as the liver matures and feeding helps excrete bilirubin.

So, five to six milligrams per deciliter is the normal range you’re most likely to see in a healthy newborn during the physiologic jaundice phase. Values much higher than that would prompt evaluation for potential causes and possible treatment, while lower values can occur earlier or in well-fed, healthy babies. Direct (conjugated) bilirubin stays low in this physiologic pattern; a rising direct fraction would suggest a different issue.