A term neonate develops jaundice on day 2 of life. Total serum bilirubin is 14 mg/dL (predominantly unconjugated). The infant is breastfed, active, and feeding well. Blood group of mother is O positive; baby is A positive; direct Coombs test is positive. Which of the following is the most likely diagnosis?
- A ABO hemolytic disease of the newborn ✓
- B Physiological jaundice
- C Breast milk jaundice
- D Crigler-Najjar syndrome type I
Correct answer: A. ABO hemolytic disease of the newborn
Explanation
ABO incompatibility occurs classically when the mother is group O and the baby is group A or B. Maternal anti-A or anti-B IgG antibodies cross the placenta and coat fetal red cells, causing hemolysis. A positive direct Coombs (DAT) confirms antibody coating of the neonatal red cells. Jaundice appearing on day 2 with hemolysis is the hallmark, distinguishing it from physiological jaundice (which is milder) and breast milk jaundice (which peaks later, around day 10-14).
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.