Clinically significant hemolytic disease of the newborn secondary to passive transfer of anti‐ D from maternal R h IG

Background R h IG is used worldwide to reduce the incidence of alloimmunization to D during pregnancy. We report a case of clinically significant neonatal hemolysis mediated by maternally administered RhIG . Case Report A 25‐year‐old, O –, primigravid mother with a negative antenatal antibody screen delivered a 6‐lb 4‐oz, blood group A , D + baby girl at 36.5 weeks' gestation. Prenatal care included a dose of intramuscular R h IG at 28 weeks' gestation. At delivery, the newborn was markedly jaundiced with a total bilirubin of 6.3 mg/ dL , which reached more than 20 mg/ dL after 6 days. The newborn's lactate dehydrogenase ( LDH ) was 485  U / L (normal, <226  U / L ) and further laboratory studies revealed reticulocytosis (17.2%; normal range, 0.36%‐1.9%) and a hemoglobin ( Hb ) of 14.3 g/ dL (normal for age range, 13.4‐19.8 g/ dL ) that decreased to 11.5 g/ dL (normal for age range, 13.5‐22.6 g/ dL ) by D ay‐of‐life 7. Although the maternal antibody screen was negative, the newborn's direct antiglobulin test ( DAT ) was positive for immunoglobulin ( Ig ) G , with an anti‐ D identified by elution studies. The possibility of hemolytic disease of the newborn ( HDN ) due to anti‐ A was considered, but ultimately ruled out by the absence of anti‐ A 1 in the eluate. The newborn's hyperbilirubinemia was adequately managed with phototherapy. Analysis of the mother's plasma 10 days postpartum revealed an anti‐ D titer of 8. Two months after birth, the child's laboratory studies, DAT , antibody screen, and peripheral smear were unremarkable. Conclusion In the context of neonatal anemia, elevated LDH , and reticulocytosis, a positive IgG DAT with anti‐ D identified in the eluate suggests RhIG ‐mediated HDN . This appears to be a rarely reported event.