In newborn physiology, which statement describes bilirubin elimination?

In newborn physiology, which statement describes bilirubin elimination?

• A. Immature liver function and inability to eliminate excess bilirubin
• B. Fully mature hepatic conjugation from birth
• C. Overactive hepatic conjugation
• D. Decreased bilirubin production

Answer: (A)

Newborn bilirubin elimination relies on the liver’s ability to conjugate unconjugated bilirubin so it can be excreted. At birth, this conjugation system is immature, so the liver cannot efficiently convert bilirubin to a water-soluble form. This leads to accumulation of unconjugated bilirubin and physiologic jaundice as levels rise before the enzyme activity matures. Over time, as hepatic conjugation capacity increases, elimination improves and bilirubin levels fall. The other statements don’t fit because the newborn liver is not fully mature from birth, conjugation isn’t overactive, and bilirubin production is not decreased (production is relatively high due to fetal red blood cell turnover).

Newborn bilirubin elimination relies on the liver’s ability to conjugate unconjugated bilirubin so it can be excreted. At birth, this conjugation system is immature, so the liver cannot efficiently convert bilirubin to a water-soluble form. This leads to accumulation of unconjugated bilirubin and physiologic jaundice as levels rise before the enzyme activity matures. Over time, as hepatic conjugation capacity increases, elimination improves and bilirubin levels fall. The other statements don’t fit because the newborn liver is not fully mature from birth, conjugation isn’t overactive, and bilirubin production is not decreased (production is relatively high due to fetal red blood cell turnover).