Impact of red blood cell alloimmunization on fetal and neonatal outcomes: A single center cohort study

Abstract

Background Alloimmunization can impact both the fetus and neonate. Study objectives: (a) calculate the incidence of clinically significant RBC isoimmunization during pregnancy, (b) review maternal management and neonatal outcomes, (c) assess the value of prenatal and postnatal serological testing in predicting neonatal outcomes. Study Design and Methods A retrospective audit of consecutive alloimmunized pregnancies was conducted. Data collected included demographics, clinical outcomes, and laboratory results. Outcomes included: incidence of alloimmunization; outcomes for neonates with and without the cognate antigen; and sensitivity and specificity of antibody titration testing in predicting hemolytic disease of the fetus and newborn (HDFN). Results Over 6 years, 128 pregnant women (0.4%) were alloimmunized with 162 alloantibodies; anti‐E was the most common alloantibody (51/162; 31%). Intrauterine transfusions (IUTs) were employed in 2 (3%) of 71 mothers of cognate antigen positive (CoAg+) neonates. Of 74 CoAg+ neonates, 58% required observation alone, 23% intensive phototherapy, 9% top up transfusion, and 3% exchange transfusion; no fetal or neonatal deaths occurred. HDFN was diagnosed in 28% (21/74) of neonates; anti‐D was the most common cause. The sensitivity and specificity of the critical gel titer >32 in predicting HDFN were 76% and 75%, respectively (negative predictive value 95%; positive predictive value 36%). The sensitivity and specificity of a positive direct antiglobulin test (DAT) in predicting HDFN were 90% and 58%, respectively (NPV 97%; PPV 29%). Conclusion Morbidity and mortality related to HDFN was low; most alloimmunized pregnancies needed minimal intervention. Titers of >32 by gel warrant additional monitoring during pregnancy.

Immunohematology testing using umbilical cord blood: review of the literature, survey of practice and guidance development

“…1,60,61 Results indicate variable positive predictive values (range 10%-78%), sensitivities (4%-88%) and specificities (73%-100%) (Table 2). 13,33,60,[62][63][64][65][66][67][68][69][70][71] Reasons for this variability are multifactorial and relate to differences in methodology of the DAT, populations studied, and outcomes measured.…”

International guidelines regarding the role of IVIG in the management of Rh‐ and ABO‐mediated haemolytic disease of the newborn

“…Despite preventative strategies, haemolytic disease of newborn (HDN) continues to occur in 3-80/10 000 neonates/ year. 1,2 HDN occurs when maternal IgG antibodies reactive to paternal blood group antigens traverse the placenta and cause immune-mediated haemolysis of fetal red blood cells (RBCs). Alloimmunization can be triggered by more than 50 blood group antigens; the most severe disease involves RhD, Rhc and K antigens.…”

Racial/ethnic disparities among women receiving intrauterine transfusions for alloimmunization at a single fetal treatment center

“…3 While serious, maternal alloimmunization is rare; at a large tertiary care institution, 0.4% of pregnant women were found to have antibodies, and of those only 3% developed HFDN and required IUT. 4 Women receiving IUT typically require multiple transfusion procedures, increasing their exposure to donor blood products and procedural complications. 5 There is increasing evidence of racial and ethnic disparities across numerous healthcare settings.…”

“…IUT has dramatically reduced the morbidity and mortality of HDFN 3 . While serious, maternal alloimmunization is rare; at a large tertiary care institution, 0.4% of pregnant women were found to have antibodies, and of those only 3% developed HFDN and required IUT 4 . Women receiving IUT typically require multiple transfusion procedures, increasing their exposure to donor blood products and procedural complications 5 …”