A 28-year-old Rh-negative mother presents with her 2-day-old newborn male who has developed severe jaundice within 24 hours of birth. The pregnancy was uncomplicated until the mother missed her 28-week RhoGAM injection. This is her second pregnancy, and her first child, also Rh-positive, was born without complications but did not receive postpartum Rh immunoprophylaxis. There is no history of maternal illness during pregnancy or any other known medical conditions. Birth History: • Full-term vaginal delivery • APGAR scores: 7 at 1 minute, 9 at 5 minutes • Birth weight: 3.2 kg (normal) Clinical Examination: • General: Lethargic, irritable, and poor suck reflex • Skin: Generalized jaundice extending to the palms and soles • Abdomen: Hepatosplenomegaly • Neurological: Mild hypotonia, decreased Moro reflex Initial Investigations: • Bilirubin: Total = 18 mg/dL (severe hyperbilirubinemia) • Hemoglobin: 9 g/dL (anemia) • Reticulocyte count: Elevated • Peripheral smear: Nucleated RBCs (erythroblasts) • Direct Coombs test: Positive for anti-D antibodies • Maternal Rh status: Rh-negative • Fetal Rh status: Rh-positive What is the most likely underlying mechanism of the newborn’s condition?
