Which feature is most consistent with physiologic jaundice in a newborn?

• A. Jaundice appears after 24 hours and peaks around day 3-5
• B. Jaundice is present at birth
• C. Jaundice persists beyond 2 weeks
• D. Jaundice decreases bilirubin quickly within 24 hours

Answer: (A)

Physiologic jaundice reflects the newborn’s normal bilirubin metabolism issues after birth. The key pattern is a rise in bilirubin that starts after the first day of life, because the liver’s ability to conjugate bilirubin isn’t fully mature yet and there’s continued high turnover of red blood cells. This typical timing—appearing after 24 hours and peaking around day 3 to 5—is what makes it characteristic of physiologic jaundice. It usually fades as the infant’s liver matures, often resolving within the first week or two in term babies.

If jaundice is present at birth, that points more toward a pathologic process or another condition; lasting beyond two weeks suggests an ongoing issue beyond physiologic jaundice; and a bilirubin level that drops within 24 hours would not fit the usual physiologic pattern, which involves a rise before it falls.