A newborn infant is jaundiced due to Rh incompatibility. Which finding is most important for the nurse to report to the healthcare provider?

• A. Bruising.
• B. Oral intake.
• C. Hemoglobin.
• D. Bilirubin.

Answer: (D)

Elevated bilirubin from fetal red cell destruction in Rh incompatibility is the key issue. When maternal antibodies attack the newborn’s Rh-positive RBCs, hemolysis raises unconjugated bilirubin. Reporting the bilirubin level and its trajectory to the provider is crucial because high bilirubin can cross the immature blood-brain barrier and cause kernicterus; this finding directly informs whether phototherapy or exchange transfusion is needed. Bruising might result from birth trauma but doesn’t reflect the ongoing hemolysis or risk of brain injury. Oral intake matters for hydration and bilirubin processing, but it doesn’t indicate the current risk to the CNS. Hemoglobin shows anemia from hemolysis, but bilirubin level is the most urgent marker guiding immediate treatment.