A newborn with unconjugated hyperbilirubinemia is started on phototherapy. What bilirubin decline is expected if therapy is effective?

Correct option is B

Effective phototherapy reduces serum bilirubin by 1–2 mg/dl every 4–6 hrs, preventing kernicterus.
Explanation of options: (a) ✘ 0.5 mg/dl in 24 hrs is too slow, inadequate. (b) ✔ Correct; 1–2 mg/dl drop in 4–6 hrs is therapeutic. (c) ✘ 0.5–1 mg/dl per 12 hrs is suboptimal. (d) ✘ 3–4 mg/dl per day is possible but not the standard indicator.