Hematology AdvisorNovel Blood Component, Specialized Care Manage High-Risk, Severe HDFN

⚠️ Single Case Report

Investigators presented a case involving a 37-year-old pregnant woman at 19 weeks’ gestation with severe hemolytic disease of the fetus and newborn (HDFN) caused by anti-ER5 antibodies. Management was complicated by multiple barriers, including maternal anemia that precluded autologous donation, ABO-related hemolysis that prevented standard intravenous immunoglobulin therapy, and the absence of readily available compatible blood products. The challenge was amplified by the rarity of ER5-negative blood. ER5 was formally recognized as a high-incidence antigen within the Er blood group system only in 2022, creating significant transfusion support limitations.

Diagnostic and Management Considerations

• An ultrarare ER5-negative donor was identified through an international donor network.
• Imported donor units were split and frozen to maximize availability throughout the pregnancy.
• The fetus received multiple intrauterine transfusions between 20 and 29 weeks’ gestation using both maternal collections and internationally sourced ER5-negative blood.
• Doppler surveillance initially demonstrated improvement but later revealed progressive fetal anemia requiring more frequent interventions.
• Technical complications necessitated transition from intravascular to intraperitoneal transfusion during later procedures.
• Following the development of fetal ascites, delivery occurred at 29 weeks’ gestation.

Learning Points

• Rare blood-group antibodies can create substantial logistical barriers to fetal transfusion support.
• International donor registries may provide critical access to ultrarare compatible blood products when local inventories are unavailable.
• Component modification strategies, including unit splitting and cryopreservation, may extend access to scarce resources.
• Successful transfusion support does not eliminate the risks associated with severe fetal alloimmune hemolysis.
• Early multidisciplinary involvement among transfusion medicine, maternal-fetal medicine, and neonatal teams is essential in highly complex HDFN cases.