Massive fetomaternal hemorrhage (FMH) is rare and reported to be the cause in approximately 3% of all fetal deaths. Maternal management of massive FMH includes prevention of Rh(D) alloimmunization in Rh(D)-negative mothers by administration of Rh(D) immune globulin (RhIG).
We describe a case of a 30-year-old O-negative, primigravida woman who presented at 38 weeks of gestation with decreased fetal movements. She underwent an emergency cesarean section and delivered an O-positive baby girl who died shortly after birth.
The patient’s FMH screen was positive, with a Kleihauer-Betke test demonstrating 10.7% fetal blood in maternal circulation. The calculated dose of 6,300 µg RhIG was given prior to discharge over 2 days using an intravenous (IV) preparation. Antibody screening a week after discharge showed anti-D and anti-C. The anti-C was attributed to acquired passive immunity from the large dose of RhIG. Anti-C reactivity waned and was negative at 6 months, but the anti-D pattern persisted at 9 months postdelivery. Negative antibody screens were noted at 12 and 14 months.
This case highlights the immunohematology challenges of IV RhIG as well as the success in preventing alloimmunization with IV RhIG given the patient’s complete resolution of anti-C and no anti-D formation, with a subsequent healthy pregnancy.

© The Author(s) 2023. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For permissions, please e-mail: