The Recurrence Risk of Fetomaternal Hemorrhage

Glucose-6-phosphate dehydrogenase deficiency as a cause for nonimmune hydrops fetalis and severe fetal anemia: A systematic review

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive disorder that predisposes individuals to hemolysis due to an inborn error of metabolism. We performed a systematic literature review to evaluate G6PD deficiency as a possible etiology of nonimmune hydrops fetalis (NIHF) and severe fetal anemia.

METHODS

PubMed, OVID Medline, Scopus, and clinicaltrials.gov were queried from inception until 31 April 2023 for all published cases of NIHF and severe fetal anemia caused by G6PD deficiency. Keywords included "fetal edema," "hydrops fetalis," "glucose 6 phosphate dehydrogenase deficiency," and "fetal anemia." Cases with workup presuming G6PD deficiency as an etiology for NIHF and severe fetal anemia were included. PRISMA guidelines were followed.

RESULTS

Five cases of G6PD-related NIHF and one case of severe fetal anemia were identified. Four fetuses (4/6, 66.7%) were male and two fetuses (2/6, 33.3%) were female. Mean gestational age at diagnosis of NIHF/anemia and delivery was 32.2 ± 4.9 and 35.7 ± 2.4 weeks, respectively. Four cases (66.7%) required a cordocentesis for fetal transfusion, and two cases (33.3%) received blood transfusions immediately following delivery. Among the four multigravida cases, two (50%) noted previous pregnancies complicated by neonatal anemia. When reported, the maternal cases included two G6PD deficiency carrier patients and two G6PD-deficient patients. Exposures to substances known to cause G6PD deficiency-related hemolysis occurred in 3/6 (50%) cases.

CONCLUSION

Six cases of NIHF/severe fetal anemia were associated with G6PD deficiency. While G6PD deficiency is an X-linked recessive condition, female fetuses can be affected. Fetal G6PD deficiency testing can be considered if parental history indicates, particularly if the standard workup for NIHF is negative.

Is Feto-Maternal Transfusion after Cesarean Delivery Different in Singleton and Twin Pregnancy?

Background: The aim of the study was to investigate if feto-maternal transfusion was related to the size of the fetal-maternal interface, and, therefore, was larger in twin pregnancy in comparison with singleton pregnancy. Methods: Blood samples from women with singleton (n = 11), and monochorionic (n = 11) and dichorionic (n = 13) twin gestations were tested. Flow cytometry tests with hemoglobin F, glycophorin A, and hemoglobin F and carbonic anhydrase simultaneous staining were used to detect fetal red blood cells and maternal F cells. Results: In all cases, the volume of feto-maternal transfusion was estimated to be low. The highest rate of fetal red blood cells in the maternal circulation was observed in the blood of women with dichorionic twin gestations both before and after delivery. An increase in fetal red blood cells was observed after cesarean section in singletons and twins. The median rate of maternal F cells was 2.23% in singleton, 2.1% in monochorionic and 3.95% in dichorionic pregnancy. Conclusions: Feto-maternal transfusion during pregnancy may be related to the multiplicity and chorionicity of pregnancy.

Red Blood Cell Alloimmunization in Pregnancy: A Review of the Pathophysiology, Prevalence, and Risk Factors

This review paper provides an overview of the risk factors and laboratory testing for red blood cell (RBC) alloimmunization in pregnancy. RBC alloimmunization is a significant medical issue that can cause haemolytic disease of the fetus and newborn (HDFN), leading to neonatal morbidity and mortality. Current HDFN prophylaxis targets only Rhesus D (RhD) alloimmunization, with no effective measures to prevent alloimmunization to other RBC antigen groups. Several factors can increase the risk of developing RBC alloimmunization during pregnancy, including fetomaternal haemorrhage, RBC and maternal genetic status, and previous transfusions. Identifying these risk factors is essential to execute the appropriate management strategies to minimize the risk of HDFN. The review also discusses the laboratory methods and overview of pregnancy management. The paper highlights the importance of identifying and managing the risk factors for RBC alloimmunization in pregnancy to minimize the risk of HDFN and improve neonatal outcomes.

Immunohematological testing and transfusion management of the prenatal patient

The primary indication for immunohematological testing in the prenatal patient is to detect and identify maternal red cell antibodies. If there are antibodies that are expected to hemolyze the fetus' red cells, their strength of reactivity must be tested, and the fetus' antigen status determined. After delivery, testing is performed to assess the extent of fetomaternal hemorrhage, as a large hemorrhage may require other therapeutic interventions. Another major role for immunohematological testing is to select blood components appropriately when intrauterine transfusion is required for fetal anemia resulting from maternal alloimmunization or some other cause. Supplementation with molecular methods has transformed the practice of immunohematology, particularly as it applies to typing for the D antigen of the Rh blood group system. Notwithstanding the advances in testing, close coordination and communication between the transfusion service and the obstetrics service are the foundation for ensuring the finest care for prenatal patients, and for new mothers and their infants. This review describes testing and transfusion practices for prenatal patients, using case presentations to highlight the management of selected immunohematological findings. It also includes a discussion of key patient management topics that are currently unresolved.

Spontaneous massive fetomaternal hemorrhage: two case reports and a literature review of placental pathology

BACKGROUND

Massive fetomaternal hemorrhage (FMH) is a rare event during pregnancy that may cause severe fetal anemia or death.

CASE PRESENTATION

This paper reports two cases of fetomaternal hemorrhage with unexplained reasons. Both cases required emergency caesarean sections for non-reassuring fetal status and were treated with neonatal blood transfusion. Fetomaternal hemorrhage was confirmed via maternal Kleihauer-Betke test.

CONCLUSION

We found parenchymal pallor, increased nucleated red blood cells (nRBCs), and syncytial knots (SKs) in the placentas, which are compatible with fetal anemia. Immunohistochemical staining indicated VEGF, CD34, and CD31 expression in the endothelial cells of the capillaries, characteristic of massive FMH placenta. This article also reviews the particular histopathological changes in FHM placenta according to the placental lesion classification system.

Prenatal diagnosis of fetomaternal hemorrhage by a novel hydrogel fluoroimmunoassay that accurately quantifies fetal haemoglobin

Objective: Fetomaternal hemorrhage (FMH) is an alloimmunization resulting caused by the incompatibility between fetal and maternal blood. For the prevention of newborn haemolytic disease (HDN), it is crucial to quantify the amount of fetomaternal hemorrhage. However, the classical Kleihauer-Betke test (K-B test) for detecting fetomaternal hemorrhage is limited by experimental tools and conditions and is not suitable for routine clinical use. Consequently, the method of prenatal diagnosis of fetomaternal hemorrhage applicable to the clinic is a topic worthy of further study. Therefore, it is worthwhile to further investigation on the clinically applicable prenatal diagnosis method for fetomaternal hemorrhage. Methods: This experiment demonstrates hydrogel's ability to separate sensitized red blood cells from soluble antibodies. Using flow cytometry the fluorescence values of sensitized red blood cells and fluorophore-labeled antibodies were measured, and the testing steps for the detection products of a novel technology were determined. The properties of a hydrogel fluoroimmunoassay were evaluated by distinguishing between the amounts of fetal and adult haemoglobin. The precision of this technology is evaluated using the Kleihauer-Betke test as a comparison. Results: This experiment compared the detection of haemoglobin fluorescence in adults (n = 2) and fetuses (n = 6). At the same time, the fluorescence intensity of different fetal haemoglobin (HbF) in adult haemoglobin (HbA) was calculated. The fluorescence value is 1.6% when the fetal hemoglobin concentration is 0.1%. Conclusion: The novel hydrogel fluoroimmunoassay can accurately determine the fluorescence intensity by flow cytometry to differentiate fetal haemoglobin from adult haemoglobin, quantitatively prenatally diagnose fetal haemoglobin, address the incompatibility between fetal and maternal blood types, and prevent alloimmunization.

A novel enzyme-linked immunostaining technique based on silk membrane for the prenatal detection of fetomaternal haemorrhage

Objective: Developing a simple, rapid, reliable, sensitive, and cost-effective method for prenatal detection of fetomaternal haemorrhage by combining multi-aperture silk membrane with enzyme-linked immunosorbent assay (ELISA), which does not require any complicated instruments and can be visually colored, so as to provide a new method for clinical detection of fetomaternal haemorrhage. Methods: As a carrier, a chemically treated silk membrane was used to immobilize anti-A/anti-B antibody reagent. PBS washed slowly after vertically dropping red blood cells. After adding biotin-labeled anti-A/anti-B antibody reagent, PBS is slowly washed, enzyme-labeled avidin is added, and TMB is used for color development after washing. Results: When there were both anti-A and anti-B fetal erythrocytes in pregnant women's peripheral blood, the final color was dark brown. When there are no anti-A and anti-B fetal red blood cells in pregnant women's peripheral blood, the final color development results do not change, which corresponds to the color of chemically treated silk membrane. Conclusion: The new enzyme-linked immunosorbent assay (ELISA) based on a silk membrane can distinguish fetal red blood cells from maternal red blood cells prenatally and can be used for prenatal detection of fetomaternal haemorrhage.

Massive fetomaternal hemorrhage: a case series and review of literature

Objectives

Massive fetomaternal hemorrhage (FMH) is a rare and difficult to diagnose event that can have catastrophic outcomes. Although many etiologies have been associated with FMH, the majority of cases are idiopathic and affect uncomplicated pregnancies. The prevailing symptom is decreased fetal movements but some cases are asymptomatic. Changes in the fetal Doppler ultrasound, a sinusoidal cardiotocographic pattern, neonatal anemia, unexplained hydrops or stillbirth can raise suspicion that such an event has occurred.

Case presentation

This article presents a case series of severe FMH diagnosed in our center between 2011 and 2020 as well as a review of the current available literature.

Conclusions

We highlight the importance of the clinician’s awareness on detecting this rare but potentially life-threatening event.

Diagnostic accuracy of Kleihauer-Betke (Kb) testing to predict fetal outcomes associated with fetomaternal hemorrhage: a retrospective cohort study

OBJECTIVE

To evaluate the diagnostic and screening utility of Kleihauer-Betke (KB) testing as a triage tool in predicting adverse fetal outcomes associated with fetomaternal hemorrhage (FMH).

STUDY DESIGN

Single center retrospective cohort study evaluated a primary composite outcome of fetal complications associated with FMH between KB-negative and KB-positive test groups. Screening tests for sensitivity, specificity, positive predictive value and negative predictive value were determined.

RESULTS

641 women (97%) had KB-negative and 22 (3%) had KB-positive tests. The primary composite outcome between KB-negative and KB-positive pregnancies was similar (30% vs. 36%, p = 0.54). Screening exhibited high specificity (97%), however, test sensitivity was poor (4%) with only moderate positive and negative predictive values (36.4 and 69.7%).

CONCLUSION

Fetal outcomes associated with FMH were not significantly different between KB-positive and KB-negative test cohorts; KB testing offers no diagnostic precision in the emergency triage evaluation of women with suspected FMH.

High diagnosis rate for nonimmune hydrops fetalis with prenatal clinical exome from the Hydrops-Yielding Diagnostic Results of Prenatal Sequencing (HYDROPS) Study

PURPOSE

Nonimmune hydrops fetalis (NIHF) presents as life-threatening fluid collections in multiple fetal compartments and can be caused by both genetic and non-genetic etiologies. We explored incremental diagnostic yield of testing with prenatal exome sequencing (ES) for NIHF following a negative standard NIHF workup.

METHODS

Participants enrolled into the Hydrops-Yielding Diagnostic Results of Prenatal Sequencing (HYDROPS) study met a strict definition of NIHF and had negative standard-of-care workup. Clinical trio ES from fetal samples and parental blood was performed at a CLIA-certified reference laboratory with clinical reports returned by geneticists and genetic counselors. Negative exomes were reanalyzed with information from subsequent ultrasounds and records.

RESULTS

Twenty-two fetal exomes reported 11 (50%) diagnostic results and five possible diagnoses (22.7%). Diagnosed cases comprised seven de novodominant disorders, three recessive disorders, and one inherited dominant disorder including four Noonan syndromes (PTPN11, RAF1, RIT1, and RRAS2), three musculoskeletal disorders (RYR1, AMER1, and BICD2), two metabolic disorders (sialidosis and multiple sulfatase deficiency), one Kabuki syndrome, and one congenital anemia (KLF1).

CONCLUSION

The etiology of NIHF predicts postnatal prognosis and recurrence risk in future pregnancies. ES provides high incremental diagnostic yield for NIHF after standard-of-care testing and should be considered in the workup.

Severe neonatal anemia affected by massive fetomaternal hemorrhage: a single-center retrospective observational study

OBJECTIVES

Massive fetomaternal hemorrhage (FMH) is a rare but sometimes life-threatening event, and surviving neonates may suffer major neurological complications. Severe neonatal anemia (SNA) affected by massive FMH is less reported in the literature. This study aims to explore the clinical characteristics, laboratory diagnoses, treatments and outcomes of SNA affected by massive FMH.

METHODS

Data were collected retrospectively from the hospital's electronic medical record system. All neonates born in the hospital and admitted to the neonatal unit diagnosed as SNA affected by massive FMH from 1 January 2013 to 31 June 2017 were included.

RESULTS

A total of 8 cases of SNA affected by FMH were identified among 6825 neonates admitted to the neonatal unit. They all presented with pallor but without hydrops at birth. Median gestational age and birthweight were 37^5/7 (36^0/7‒40^1/7) weeks and 2,625 (2300‒3050) g, respectively. Median hemoglobin level was 39.5 (25‒53) g/L at birth and 109.5 (94-127) g/L at discharge. Median maternal serum alpha-fetoprotein (AFP) was 3958.5 (1606‒14,330) ng/mL, which was significantly increased. Three out of eight cases manifested as antenatal decreased fetal movement. Only 1 with the lowest initial hemoglobin 25 g/L manifested as characteristic sinusoidal fetal heart rate tracing and suffered severe neonatal asphyxia and hypovolemic shock. Having experienced resuscitation, he was admitted to the neonatal unit and received twice transfusion of cross-matched red blood cells there. Another case with the initial hemoglobin 45 g/L received positive pressure ventilation and once transfusion. All cases were successfully discharged with a median hospital stay of 8 (5-12) days. Follow-up was available for 6 (75%) of 8 neonates (age range 13 months to 50 months), and all infants were observed to be in good condition with normal neurological status. In our series of eight cases, there were no neonatal deaths.

CONCLUSION

This study strengthens the idea that maternal AFP testing is valuable to confirm massive fetomaternal hemorrhage. Surviving neonates of massive FMH might have a good outcome despite severe anemia at birth.

Evaluation of machine learning-driven automated Kleihauer-Betke counting: A method comparison study

INTRODUCTION

The Kleihauer-Betke (KB) test is the diagnostic standard for the quantification of fetomaternal hemorrhage (FMH). Manual analysis of KB slides suffers from inter-observer and inter-laboratory variability and low efficiency. Flow cytometry provides accurate quantification of FMH with high efficiency but is not available in all hospitals or at all times. We have developed an automated KB counting system that uses machine learning to identify and distinguish fetal and maternal red blood cells (RBCs). In this study, we aimed to evaluate and compare the accuracy, precision, and efficiency of the automated KB counting system with manual KB counting and flow cytometry.

METHODS

The ratio of fetal RBCs of the same blood sample was quantified by manual KB counting, automated KB counting, and flow cytometry, respectively. Forty patients were enrolled in this comparison study.

RESULTS

Comparing the automated KB counting system with flow cytometry, the mean bias in measuring the ratio of fetal RBCs was 0.0048%, with limits of agreement ranging from -0.22% to 0.23%. Using flow cytometry results as a benchmark, results of automated KB counting were more accurate than those from manual counting, with a lower mean bias and narrower limits of agreement. The precision of automated KB counting was higher than that of manual KB counting (intraclass correlation coefficient 0.996 vs 0.79). The efficiency of automated KB counting was 200 times that of manual counting by the certified technologists.

CONCLUSION

Automated KB counting provides accurate and precise FMH quantification results with high efficiency.

A Silicon-based Coral-like Nanostructured Microfluidics to Isolate Rare Cells in Human Circulation: Validation by SK-BR-3 Cancer Cell Line and Its Utility in Circulating Fetal Nucleated Red Blood Cells

Circulating fetal cells (CFCs) in maternal blood are rare but have a strong potential to be the target for noninvasive prenatal diagnosis (NIPD). "Cell Reveal^TM system" is a silicon-based microfluidic platform capable to capture rare cell populations in human circulation. The platform is recently optimized to enhance the capture efficiency and system automation. In this study, spiking tests of SK-BR-3 breast cancer cells were used for the evaluation of capture efficiency. Then, peripheral bloods from 14 pregnant women whose fetuses have evidenced non-maternal genomic markers (e.g., de novo pathogenic copy number changes) were tested for the capture of circulating fetal nucleated red blood cells (fnRBCs). Captured cells were subjected to fluorescent in situ hybridization (FISH) on chip or recovered by an automated cell picker for molecular genetic analyses. The capture rate for the spiking tests is estimated as 88.1%. For the prenatal study, 2⁻71 fnRBCs were successfully captured from 2 mL of maternal blood in all pregnant women. The captured fnRBCs were verified to be from fetal origin. Our results demonstrated that the Cell Reveal^TM system has a high capture efficiency and can be used for fnRBC capture that is feasible for the genetic diagnosis of fetuses without invasive procedures.