HDFN Resulting from Anti-U: Alternatives to Allogeneic Intrauterine Transfusion

Hemolytic disease of the fetus and newborn (HDFN) carries significant fetal mortality risks. Although anti-D as a source of HDFN has been prevented for decades using D-specific immunoglobulin to prevent alloimmunization between fetus and mother, minor blood groups may still result in disease, with potentially disastrous consequences if left untreated. Strategies such as intrauterine transfusion, early delivery, and vigilant serologic monitoring of fetal anemia have been the standards of care for alloimmunized patients, but beyond this not much more is possible. Mothers with rare phenotypes who are alloimmunized against extremely common red blood cell antigens may find access to rare antigen-negative blood units limited. This case study presents a healthy G10P6 woman with known anti-U presenting for treatment via intrauterine transfusion in the second trimester and follows the patient through successful delivery. Difficulties in obtaining rare blood for the patient because of concomitant delivery events involving 2 patients with anti-U at the facility opened discussions about the difficulties of and alternatives to intrauterine transfusion where rare blood phenotypes are involved.