Clinically silent massive fetomaternal hemorrhage: important lessons from an illustrative case.
Massive fetomaternal hemorrhage (FMH) >150 mL is rare and may occur in the absence of high-risk obstetrical events. The significance of FMH in Rh D-negative women is alloimmunization with an increased risk of hemolytic disease of the newborn in subsequent Rh D-positive pregnancies and adverse outcomes for the fetus/neonate. The Kleihauer-Betke (KB) acid elution test is used to quantify fetal erythrocytes in the circulation of Rh D-negative women postpartum and to calculate the dose of Rh immune globulin (RhIG) needed for prophylaxis against alloimmunization. In this case, the KB stain unexpectedly revealed 4.5% fetal cells, a finding consistent with a massive FMH of 225 mL, in the absence of a predisposing cause and clinical signs in the infant. This case underscores the importance of FMH quantification in all Rh D-negative women with Rh D-positive fetuses, uncomplicated pregnancies, and healthy newborns. We discuss factors that can affect KB test performance and caveats in interpretation.
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. gpost@uams.edu
Ginell R
GR
Post
John
J
Lazarchick
Zeba N
ZN
Singh
D005260:Female; D005331:Fetomaternal Transfusion / Q000175:diagnosis* / Q000628:therapy; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000175:diagnosis / Q000628:therapy; D012203:Rh Isoimmunization / Q000175:diagnosis / Q000628:therapy; D018029:Rho(D) Immune Globulin / Q000627:therapeutic use; D055815:Young Adult
D018029:Rho(D) Immune Globulin