Detection of fetomaternal hemorrhage

Abstract

The prevention of Rhesus D alloimmunization through Rh immune globulin (RhIg) administration is the major indication for the accurate detection and quantification of fetomaternal hemorrhage (FMH). In the setting of D incompatibility, D-positive fetal cells can sensitize the D-negative mother, resulting in maternal anti-D alloantibody production. These anti-D alloantibodies may lead to undesirable sequelae such as hemolytic disease of the newborn (HDN). Since the widespread adoption of FMH screening and RhIg immunoprophylaxis, the overall risk of Rh alloimmunization and infant mortality from HDN has substantially decreased. The rosette screen, the initial test of choice, is highly sensitive in qualitatively detecting 10 mL of fetal whole blood in the maternal circulation. As the screen is reliant on the presence of the D antigen to distinguish fetal from maternal cells, it cannot be used to detect FMH in D-positive mothers or in D-negative mothers carrying a D-negative fetus. The Kleihauer-Betke acid-elution test, the most widely used confirmatory test for quantifying FMH, relies on the principle that fetal RBCs contain mostly fetal hemoglobin (HbF), which is resistant to acid-elution whereas adult hemoglobin is acid-sensitive. Although the Kleihauer-Betke test is inexpensive and requires no special equipment, it lacks standardization and precision, and may not be accurate in conditions with elevated F-cells. Anti-HbF flow cytometry is a promising alternative, although its use is limited by equipment and staffing costs. Hematology analyzers with flow cytometry capabilities may be adapted for fetal cell detection, thus giving clinical laboratories a potentially attractive automated alternative for quantifying FMH. Am. J. Hematol. 87:417-423, 2012. V

Changes in hemoglobin F levels in pregnant women unaffected by clinical fetomaternal hemorrhage

“…A diagnosis of clinical fetomaternal hemorrhage (FMH) is made when fetal blood loss reaches a significant level leading to fetal anemia and clinical symptoms, such as an abnormal fetal heart rate patterns and/or fetal hydrops [3]. Although clinical FMH is rare, affected fetuses may survive with cerebral palsy, which accounts for approximately 2.0% of infants with cerebral palsy caused by antenatal and/or intrapartum hypoxic conditions [4].…”

Síndrome de Transfusión Feto-Materna. A propósito de dos casos.

“…Su principal limitación es precisamente la necesidad de una incompatibilidad de grupo materno-fetal para poder hacer el diagnóstico. 28 .…”

“…Su desventaja, sin embargo, radica en la escasa disponibilidad de este recurso en la práctica clínica habitual. 28 .…”

Hemorragia feto-materna grave como causa de encefalopatia hipóxico-isquémica

“…9 Perante a suspeita de HFM, o sangue materno deve ser testado para verificar a presença de glóbulos vermelhos fetais. 7,9,12 Atualmente, estão disponíveis dois tipos de exames, o teste de Kleihauer-Betke e a citometria de fluxo. Ambos são baseados na identificação de hemoglobina F e medem a quantidade de sangue fetal na circulação materna num dado momento.…”

“…5,7,12 Relativamente ao tratamento, importa realçar que, se o diagnóstico for feito em tempo útil, podem ser tomadas algumas medidas terapêuticas que reduzem significativamente a morbimortalidade. Estas atitudes passam pela transfusão intrauterina, nas gestações pré-termo, ou pela realização de uma cesariana emergente, com transfusão neonatal imediata, nas gestações perto do termo.…”