Detection of fetomaternal hemorrhage

Made to move: A review of measurement strategies to characterize heterogeneity in normal fetal movement

Fetal movement is a crucial indicator of fetal well-being. Characteristics of fetal movement vary across gestation, posing challenges for researchers to determine the most suitable assessment of fetal movement for their study. We summarize the current measurement strategies used to assess fetal movement and conduct a comprehensive review of studies utilizing these methods. We critically evaluate various measurement approaches including subjective maternal perception, ultrasound, Doppler ultrasound, wearable technology, magnetocardiograms, and magnetic resonance imaging, highlighting their strengths and weaknesses. We discuss the challenges of accurately capturing fetal movement, which is influenced by factors such as differences in recording times, gestational ages, sample sizes, environmental conditions, subjective perceptions, and characterization across studies. We also highlight the clinical implications of heterogeneity in fetal movement assessment for monitoring fetal behavior, predicting adverse outcomes, and improving maternal attachment to the fetus. Lastly, we propose potential areas of future research to overcome the current gaps and challenges in measuring and characterizing abnormal fetal movement. Our review contributes to the growing body of literature on fetal movement assessment and provides insights into the methodological considerations and potential applications for research.

Comparison of the Detection Rate and Specificity of Irregular Red Blood Cell Antibodies Between First-Time Pregnant Women and Women With a History of Multiple Pregnancies Among 18,010 Chinese Women

Background: There is insufficient evidence to assess the risk of the production of clinically important alloimmune irregular red blood cell (RBC) antibodies in first-time pregnant women. Methods: Using the microcolumn gel antiglobulin method, 18,010 Chinese women with a history of pregnancy and pregnant women were screened for irregular RBC antibodies, and for those with positive test results, antibody specificity was determined. The detection rate and specificity of irregular RBC antibodies in women with a history of multiple pregnancies (two or more) and first-time pregnant women were determined. Results: In addition to 25 patients who passively acquired anti-D antibodies via an intravenous anti-D immunoglobulin injection, irregular RBC antibodies were detected in 121 (0.67%) of the 18,010 women. Irregular RBC antibodies were detected in 93 (0.71%) of the 13,027 women with a history of multiple pregnancies, and antibody specificity was distributed mainly in the Rh, MNSs, Lewis, and Kidd blood group systems; irregular RBC antibodies were detected in 28 (0.56%) of the 4983 first-time pregnant women, and the antibody specificity was distributed mainly in the MNSs, Rh, and Lewis blood group systems. The difference in the percentage of patients with irregular RBC antibodies between the two groups was insignificant (χ 2 = 1.248, P > 0.05). Of the 121 women with irregular RBC antibodies, nine had anti-Mur antibodies, and one had anti-Dia antibodies; these antibodies are clinically important but easily missed because the antigenic profile of the reagent RBCs that are commonly used in antibody screens does not include the antigens that are recognized by these antibodies. Conclusion: Irregular RBC antibody detection is clinically important for both pregnant women with a history of multiple pregnancies and first-time pregnant women. Mur and Dia should be included in the antigenic profile of reagent RBCs that are used for performing antibody screens in the Chinese population.

HPLC and flow cytometry combined approach for HbF analysis in fetomaternal haemorrhage evaluation

Introduction

Recently, a flow cytometric (FC) based test has been developed for detection of circulating fetal cells to replace the less accurate and reproducible Kleihauer-Betke test.FC test is easier to perform, it can distinguish the origin of fetal cells, but it is expensive and available in highly specialized laboratories. We evaluated the introduction of high-performance liquid chromatography (HPLC) approach as initial screening to identify patients who need an additional FC test to better discriminate the nature of haemoglobin-F (HbF) positive cells.

Methods

Blood samples from 130 pregnant women suspected to have fetomaternal haemorrhage were analysed with HPLC and FC methods. The cut-off for HbF HPLC concentration was calculated. Statistical analyses for the evaluation of HPLC as a screening method were performed. The positivity cut-off of HbF to be used as decision-making value to continue the investigation was calculated.

Results

An excellent agreement (R2 > 0.90) was observed between the percentage of HbF obtained by HPLC and the percentage of fetal cells detected by FC. Results obtained from each assay were compared to define the HPLC threshold below which it is not necessary to continue the investigations, confirming the maternal nature of the HbF positive cells detected. Our study demonstrated that a cut-off of 1.0 % HbF obtained by HPLC was associated with the lowest rate of false negative results in our patient cohort.

Conclusions

This study provides a new FMH investigation approach that possibly leads to a reduction in times and costs of the analysis.

Massive fetomaternal hemorrhage: A case report

We present a case with an incidental finding of abnormal cardiotocography (CTG) pattern as well as elevated middle cerebral artery peak systolic velocity (MCA-PSV) in an otherwise inconspicuous pregnancy. Massive fetomaternal hemorrhage (FMH) was detected as the cause by flow cytometry (FC), resulting in multiple cycles of fetal blood sampling (FBS) showing severe anemia, intrauterine transfusions (IUTs), a preterm delivery, and a healthy infant in follow-up examinations.

Development of a new staining protocol for the Kleihauer-Betke test to facilitate the reading of difficult cases

BACKGROUND

The Kleihauer-Betke (KB) test allows the detection of fetal red blood cells (containing fetal hemoglobin, HbF) in the maternal blood to identify and quantify potential fetal-maternal hemorrhages. In certain cases, detecting fetal red blood cells with conventional staining is difficult. False-positive results or overestimation of the quantity of fetal red blood cells may occur in cases of maternal hemoglobinopathy. In this study, we developed a new staining protocol to facilitate the reading of difficult smears and improve the precision of the quantification of fetal red blood cells; we also analyzed the performance of this new method. This study assessed blood samples with and without hemoglobin abnormalities, which present difficulties when interpreting the KB test.

METHODS

The new staining formula is based on an improved elution technique and the use of a different stain instead of hematoxylin. To test this staining method, 16 samples from patients with abnormal hemoglobin electrophoresis and 14 samples from patients with normal hemoglobin electrophoresis were analyzed using the KB test with the classical staining method and the new staining method. In addition, a second series was prepared using the same samples spiked with fetal red blood cells from newborn blood, to compare the accuracy of the two methods in identifying fetal red blood cells.

RESULTS

In the 60 slides analyzed with both staining methods, we found that the new technique improved the accuracy from 78 to 85%; lowered the coefficient of variation between the operators, which decreased from 20.7% to 12.7%; increased the specificity in our population from 56 to 70%; and decreased the number of false-positive cases by 30%.

CONCLUSIONS

We successfully developed a new staining technique that facilitates the reading of difficult slides and improves the specificity of the detection of fetal red blood cells. This technique is recommended as a secondary method to use before sending the sample for additional exploration.

Massive fetomaternal haemorrhage warranting novel use of tandem isovolumetric partial exchange transfusion and therapeutic hypothermia

A newborn male infant was pale, hypotonic, and had respiratory distress after delivery. Venous cord blood gas revealed a severe metabolic acidosis. His initial examination was consistent with moderate encephalopathy and laboratory testing uncovered severe congenital anaemia (haematocrit 0.127 L/L). He met the clinical criteria for therapeutic hypothermia (TH) and required red blood cell transfusions, but due to the severity of his anaemia, an exchange transfusion was favoured to prevent transfusion-associated circulatory overload. There are no previous reports of these procedures completed in tandem, but the benefits were perceived to outweigh the risks. During the 72 hours of TH, the infant received an isovolumetric partial exchange transfusion and tolerated both treatments without any adverse clinical events.Kleihauer-Betke testing detected a massive chronic fetomaternal haemorrhage with 475 mL (164 mL/kg) of blood. A brain MRI completed prior to discharge was normal. At 6 months of age, he is growing and developing normally.

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.

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.

A Case of Massive Fetal-Maternal Hemorrhage: Lessons Learned in Diagnosis and Treatment

The use of Rho(D) immune globulin in Rh-negative pregnant women has become standard of care, but many practicing clinicians do not know the dosing recommendations for this essential medication. In this article, we describe a case of a 15-year-old girl who presented with intrauterine fetal demise and was found to have massive fetomaternal hemorrhage. Kleihauer-Betke testing results indicated nearly 460 mL of fetal blood in the maternal circulation. The patient ultimately received 4800 µg of Rho(D) immune globulin, a dose that required close coordination with the obstetrical service and pharmacy. Although this is an unusual case of large-volume, potentially chronic, fetomaternal hemorrhage, it is also an excellent illustration of the principles for diagnosing this condition, as well as providing dosing guidelines for Rho(D) immunoglobulin to prevent alloimmunization.

Antigen copy number and antibody dose can determine the outcome of erythrocyte alloimmunization inducing either antibody-mediated immune suppression or enhancement in a murine model

BACKGROUND

The administration of anti-D for the prevention of hemolytic disease of the fetus and newborn is one of the most successful clinical uses of the phenomenon of antibody-mediated immune suppression (AMIS). However, despite adequate prophylaxis, failures can still occur in the clinic and are poorly understood. Recently, the copy number of red blood cell (RBC) antigens has been shown to influence immunogenicity in the context of RBC alloimmunization; however, its influence on AMIS remains unexplored.

STUDY DESIGN AND METHODS

RBCs expressing approximately 3,600 and approximately 12,400 copy numbers of surface-bound hen egg lysozyme (HEL), named respectively HELmed -RBCs and HELhi -RBCs, and selected doses of a polyclonal HEL-specific IgG were transfused into mice. Recipient HEL-specific IgM, IgG, and IgG subclass responses were evaluated by ELISA.

RESULTS

Antigen copy number affected the antibody dose required for AMIS induction with higher antigen copy numbers requiring larger doses of antibody. For instance, 5 μg of antibody caused AMIS for HELmed -RBCs but not HELhi -RBCs, while 20 μg induced significant suppression for both HEL-RBCs. Overall, increasing amounts of the AMIS-inducing antibody were associated with a more complete AMIS effect. In contrast, the lowest tested doses of the AMIS-inducing IgG led to evidence of enhancement at the IgM and IgG levels.

DISCUSSION

The results demonstrate that the relationship between antigen copy number and antibody dose can influence the outcome of AMIS. Further, this work suggests that the same antibody preparation can induce both AMIS and enhancement but that the outcome may depend on the quantitative interrelationship of antigen-antibody binding.

Antigen-specific IgG subclass composition in recipient mice can indicate the degree of red blood cell alloimmunization as well as discern between primary and secondary immunization

BACKGROUND

Despite the vast antigen disparity between donor and recipient red blood cells (RBCs), only 2%-6% of transfusion patients mount an alloantibody response. Recently, RBC antigen density has been proposed as one of the factors that can influence alloimmunization, however, there has been no characterization of the role of antigen density along with RBC dose in primary and secondary immunization.

STUDY DESIGN AND METHODS

To generate RBCs that express distinct antigen copy numbers, different quantities of hen egg lysozyme (HEL) were coupled to murine RBCs. The HEL-RBCs were subsequently transfused into recipient mice at different RBC doses and their HEL-specific IgM, IgG, and IgG subclass response was evaluated.

RESULTS

Productive immune responses could be generated through a high copy number antigen transfused at low RBC doses or a low copy number transfused at high RBC doses. Further, primary but submaximal humoral immunization predominantly induced the IgG2b and IgG3 subclasses. In contrast, a maximal primary immunization or a secondary immunization induced all four IgG subclasses.

DISCUSSION

Our results confirm the existence of an antigen threshold for productive immune responses but indicate that a high antigen copy number alone might not be enough to induce a response, but rather a combination of both antigen copy number and cell dosage may determine the outcome of immunization. Further, this study provides a proof of concept that the IgG subclass composition can be an indicator of the level of RBC alloimmunization as well as discern between primary and secondary immunization at least in this murine model.

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.

Time points and risk factors for RhD immunizations after the implementation of targeted routine antenatal anti-D prophylaxis: A retrospective nationwide cohort study

INTRODUCTION

Targeted routine antenatal anti-D prophylaxis was introduced to the national prophylaxis program in Finland in late 2013. The aim of this study was to assess the incidence, time-points, and risk factors for Rhesus D immunization after the implementation of routine antenatal anti-D prophylaxis, in all women in Finland with antenatal anti-D antibodies detected in 2014-2017.

MATERIAL AND METHODS

In a nationwide population-based retrospective cohort study, the incidence, time-points, and risk factors of anti-D immunizations were analyzed. Information on antenatal screening was obtained from the Finnish Red Cross Blood Service database, and obstetric data from hospital records and the Finnish Medical Birth Register.

RESULTS

The study included a total of 228 women (197 with complete data for all pregnancies). After the implementation of routine antenatal anti-D prophylaxis, the prevalence of pregnancies with anti-D antibodies decreased from 1.52% in 2014 to 0.88% in 2017, and the corresponding incidence of new immunizations decreased from 0.33% to 0.10%. Time-points for detection of new anti-D antibodies before and after 2014 were the first screening sample at 8-12 weeks of gestation in 52% versus 19%, the second sample at 24-26 weeks in 20% versus 50%, and the third screening at 36 weeks in 28% versus 32%.

CONCLUSIONS

The incidence of new anti-D immunizations decreased as expected after the implementation of routine antenatal anti-D prophylaxis. True failures are rare and they mainly occur when the prophylaxis is not given appropriately, suggesting a need for constant education of healthcare professionals on the subject.

Image Analysis Using Machine Learning for Automated Detection of Hemoglobin H Inclusions in Blood Smears - A Method for Morphologic Detection of Rare Cells

Background

Morphologic rare cell detection is a laborious, operator-dependent process which has the potential to be improved by the use of image analysis using artificial intelligence. Detection of rare hemoglobin H (HbH) inclusions in red cells in the peripheral blood is a common screening method for alpha-thalassemia. This study aims to develop a convolutional neural network-based algorithm for the detection of HbH inclusions.

Methods

Digital images of HbH-positive and HbH-negative blood smears were used to train and test the software. The software performance was tested on images obtained at various magnifications and on different scanning platforms. Another model was developed for total red cell counting and was used to confirm HbH cell frequency in alpha-thalassemia trait. The threshold minimum red cells to image for analysis was determined by Poisson modeling and validated on image sets.

Results

The sensitivity and specificity of the software for HbH+ cells on images obtained at ×100, ×60, and ×40 objectives were close to 91% and 99%, respectively. When an AI-aided diagnostic model was tested on a pilot of 40 whole slide images (WSIs), good inter-rater reliability and high sensitivity and specificity of slide-level classification were obtained. Using the lowest frequency of HbH+ cells (1 in 100,000) observed in our study, we estimated that a minimum of 2.4 × 10⁶ red cells would need to be analyzed to reduce misclassification at the slide level. The minimum required smear size was validated on 78 image sets which confirmed its validity.

Conclusions

WSI image analysis can be utilized effectively for morphologic rare cell detection. The software can be further developed on WISs and evaluated in future clinical validation studies comparing AI-aided diagnosis with the routine diagnostic method.

Fetal-Maternal Hemorrhage in First-Trimester Intrauterine Hematoma

OBJECTIVE

The objective of this study was to compare the frequency and percentage of fetal hemoglobin (HbF%) by flow cytometry of (1) first-trimester asymptomatic patients with intrauterine hematoma (IUH), (2) first-trimester pregnant patients with vaginal bleeding (VB), and (3) first-trimester asymptomatic pregnant women without hematoma.

METHODS

Prospective study involving pregnant women in the first trimester of pregnancy. Patients with ultrasound findings of asymptomatic hematoma and with VB were paired with asymptomatic pregnant women of same gestational age without hematoma (control group [CG]). Maternal blood HbF% was evaluated by flow cytometry. The groups were compared in terms of circulating fetal hemoglobin and HbF%.

RESULTS

Sixty-six patients were selected, 22 with hematoma, 17 with bleeding, and 27 in the CG. Fetal hemoglobin was detected in 15 patients with hematoma (68.2%) and 13 with bleeding (76.5%) and in 20 of the control (74.1%) (p = 0.830). The mean HbF% of each group was 0.054, 0.012, and 0.042 for hematoma, bleeding, and control, respectively, and differences were not significant (p = 0.141). There was a moderate negative correlation between the volume of hematoma and HbF% (rSpearman = -0.527; p = 0.012).

CONCLUSIONS

The fetal-maternal hemorrhage expressed by Hbf% in first-trimester pregnancies did not seem to differ between patients with and without ultrasound findings of IUH.

Management of Pelvic Ring Injury Patients With Hemodynamic Instability

Pelvic ring injuries (PRI) are among the most difficult injuries to deal with in orthopedic trauma. When these injuries are accompanied by hemodynamic instability their management becomes significantly more complex. A methodical assessment and expeditious triage are required for these patients followed by adequate resuscitation. A major triage decision is whether these patients should undergo arterial embolization in the angiography suit or prompt packing and pelvic stabilization in the operating room. Patient characteristics, fracture type and injury characteristics are taken into consideration in the decision-making process. In this review we discuss the acute evaluation, triage and management of PRIs associated with hemodynamic instability. An evidence based and protocol driven approach is necessary in order to achieve optimal outcomes in these patients.

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.

Reduced fetal movement during pregnancy: Is the Kleihauer-Betke test really useful?

INTRODUCTION

Reduced fetal movement (rFM) is a frequent cause of consultation during the pregnancy and can reveal feto-maternal hemorrhage (FMH) that is sometimes responsible of severe fetal anemia. Our primary objective was to evaluate the contribution of the KBT in case of rFM. Our secondary objective was to compare it with ultrasound examination including peak systolic velocity of the middle cerebral artery (MCA-PSV) to predict neonatal anemia.

MATERIALS AND METHODS

We conducted a retrospective study from January 2016 to December 2017 at Armand-Trousseau Hospital in Paris. We analyzed all patients consulting for rFM from 18 to 41 weeks of gestation. We compared the performance of KBT and MCA-PSV to predict neonatal anemia (Hemoglobin at birth under 13.5 g/dL) and severe neonatal anemia (Hb < 10 g/dL).

RESULTS

Among the 338 patients, 327 KBT (96.7%) were performed. KBT was found positive in three cases (0.9%). Only one neonate (0.3%) presented with severe anemia requiring a postnatal transfusion. MCA-PSV was performed in 166 cases (49.1%). KBT and MCA-PSV were significantly correlated with neonatal hemoglobin at birth. KBT was better than MCA-PSV to predict neonatal anemia, while MCA-PSV was better than KBT to predict moderate to severe anemia. The KBT and MCA-PSV Doppler had excellent sensitivity and predictive negative values (100%), but they had poor predictive positive values for severe neonatal anemia.

CONCLUSION

In case of decreased fetal movement, we suggest performing fetal cerebral Doppler. MCA-PSV could suffice in first approach. KBT may be performed if there is suspicion of fetal anemia in order to confirm FMH.

The prevalence of an elevated F cell population in a maternal and gynaecology cohort

OBJECTIVES

This study aimed to determine F cell prevalence in a cohort of maternal and gynaecology specimens using QuikQuant anti-HbF flow cytometry (FC) kit and to investigate if the presence of maternal F cells can lead to fetomaternal haemorrhage (FMH) overestimation.

BACKGROUND

The gold standard to estimate FMH is the Kleihauer-Betke test (KBT). The KBT has proved to be insufficiently sensitive to detect low numbers of circulating fetal cells due to the presence of maternal F cells. At present, the prevalence of false positive KBT results due to raised maternal F cell population, defined as >5%, is poorly characterised.

METHODS

A total of 120 specimens were tested for the presence of F cells and fetal cells by KBT and anti-HbF FC. The results calculated were compared to determine FMH overestimation.

RESULTS

Of our cohort, 32% showed an elevated F cell population, of which 69% (27 of 39) were clinically significant according to KBT (>2 mL FMH). The mean FMH volumes by KBT and anti-HbF FC were 3·90 mL (0·20-35·40 mL) and 4·09 mL (0·20-9·70 mL), respectively.

CONCLUSION

The study highlighted that an elevated F cell level could be found in the cohort tested, with an F cell level of >10% causing significant FMH overestimation by KBT.

Fetomaternal Bleeding and Neonatal Hematocrit following Cesarean Delivery: Routine versus Transplacental Transection

Objective  To evaluate fetomaternal bleeding following routine cesarean delivery compared with cesarean delivery involving transplacental transection. Study Design  A prospective cohort study evaluating cesarean delivery in which the placenta was transected (cases) versus controls (placenta not transected) from January 2016 to April 2018. A maternal Kleihauer-Betke's (KB) test and newborn hematocrit were performed shortly after delivery. Results  The rate of a positive KB test was not significantly different between cases ( n  = 31) and controls ( n  = 61) (19 vs. 14%; odds ratio [OR]: 1.44; 95% confidence interval [CI]: 0.46-4.49; p  = 0.74). Median neonatal hematocrits were not different. However, the rate of newborn hematocrits <40% at delivery was higher in cases compared with controls (23 vs. 3%; OR: 8.90; 95% CI: 1.72-45.90; p  = 0.005). Conclusion  A cesarean requiring transplacental transection to accomplish delivery does not significantly increase the rate of fetomaternal bleeding but is associated with a higher likelihood of newborn hematocrit <40% at delivery.

Case Report of Anemia Following Fetal-Maternal Hemorrhage

BACKGROUND

Any maternal history of blood loss, ABO or Rh incompatibility, and hydrops fetalis often leads to suspicion of neonatal anemia postnatally. When maternal history consists only of decreased fetal movement, recognition of neonatal anemia can be problematic.

CLINICAL FINDINGS

This case was a transported late preterm neonate who presented initially with persistent hypoxia unresponsive to usual respiratory support. On examination, mild paleness was noted.

PRIMARY DIAGNOSIS

Anemia caused by fetal-maternal hemorrhage was the ultimate diagnosis confirmed by a Kleihauer-Betke test on maternal serum examining fetal cells.

INTERVENTIONS

Neonatal resuscitation included positive pressure ventilation, oxygen, and intubation. However, oxygenation did not improve prompting consultation with the neonatologist. Sedation and a paralytic were given. A chest radiograph ruled out pneumothoraces and pleural effusions as causative. Initiation of inhaled nitric oxide produced a mild response. Eventually, the transport nurse obtained a complete blood count indicating severe anemia, which prompted an emergent blood transfusion. The accepting neonatology team consulted with the obstetrician and a Kleihauer-Betke test was performed on mother's blood confirming a large fetal-maternal hemorrhage.

OUTCOMES

This neonate responded well to blood transfusions, a pressor, and respiratory support and was discharged home at 7 days of life.

PRACTICE RECOMMENDATIONS

Recognition of postnatal anemia is vital to sustaining life and this can occur in the transport environment. When maternal history is nonspecific and a neonate is hypoxic, uncommon causes of hypoxia can be identified with consultation and a complete blood count.

Establishing the Cause of Anemia in a Premature Newborn Infant

The three major causes of anemia in neonates are blood loss, decreased red blood cell production, and increased degradation of erythrocytes. Establishing the cause of anemia in a neonate born prematurely can be challenging. Clinically, fetomaternal hemorrhage (FMH) can be difficult to diagnose-the condition often presents only after the manifestation of severe fetal anemia. FMH can be confirmed by determining the fetal hemoglobin F fraction in the mother, which is traditionally performed using the Kleihauer-Betke test (KBT). Herein, we present a case study of a newborn baby boy of Dutch ethnicity with massive FMH and negative KBT result. The KBT result appeared to be false-negative due to AO antagonism. However, the results of an additional marker alpha-fetoprotein (AFP) test confirmed the diagnosis of massive FMH. Therefore, measuring AFP in maternal blood can be helpful in confirming FMH in unexplained anemia of the neonate.

Red Blood Cell Alloimmunization in the Pregnant Patient

Alloimmunization to red blood cell (RBC) antigens represents a challenge for physicians caring for women of child bearing potential. Exposure to non-self RBC antigens may occur during transfusion or pregnancy leading to the development of antibodies. If a subsequent fetus bears that antigen, maternal antibodies may attack the fetal red blood cells causing red cell destruction and clinically significant hemolytic disease of the fetus and newborn (HDFN). In the most severe cases, HDFN may result in intrauterine fetal demise due to high output cardiac failure, effusions and ascites, known as "hydrops fetalis". This article reviews strategies for management and prevention of RBC alloimmunization in women of child bearing potential.

Mild-to-moderate foeto-maternal haemorrhage in the third trimester and at term of pregnancy: quantitative determination and clinical-diagnostic evaluation

BACKGROUND

Foeto-maternal haemorrhage (FMH), a gestational event that occurs before or during delivery, consists of a loss of foetal blood into the maternal circulation. FMH occurs more frequently during the third trimester or labour both in normal and complicated pregnancies. In the case of alloimmunisation, the maternal immunological response and the severity of the resulting foetal or neonatal disease depend on the amount of foetal blood that passes into the maternal circulation. The aim of this study was to determine FMH in the third trimester and at term of pregnancy and to evaluate the role of clinical and ultrasound markers in the prediction of FMH.

MATERIALS AND METHODS

FMH was quantified by cytofluorimetric testing at 28 to 35 weeks of gestation in 223 women and at term in 465 women, all with risk factors. Foetal evaluation included foetal movement profile, middle cerebral artery peak velocity of systolic blood flow (MCA-PSV) and cardiotocographic monitoring.

RESULTS

All women tested negative for FMH in the third trimester. Four patients (0.9%) tested positive at term, with estimated volumes of bleeding of 2.2, 8.1, 12.3 and 39.8 mL. Three FMH cases (75%) had a non-reassuring cardiotocography compared to 8.9% (42/461) of women without FMH (p=0.003) and two FMH cases reported a reduction in foetal movements reduction compared to four of those without FMH (p=0.001). Mean MCA-PSV was normal in both the groups with and without FMH (p=0.22).

DISCUSSION

FMH is rare in pregnancy and at term. Cytofluorimetric testing is a specific method to detect mild-to-moderate FMH even when the MCA-PSV is not informative. Mild-to-moderate FMH is significantly associated with reduced foetal movements and non-reassuring cardiotocographic monitoring.

Placental Pathologic Features in Fetomaternal Hemorrhage Detected By Flow Cytometry

Background Fetomaternal hemorrhage (FMH) is a poorly understood entity that can have significant clinical effects. Flow cytometry is a reliable and relatively new method for FMH diagnosis. The objective of this study was to correlate placental pathology with FMH detected by flow cytometry. Methods All patients with available placentas and FMH flow cytometric testing performed from 2009 to 2015 were retrospectively reviewed. Cases were defined as ≥0.10% fetal red blood cells (RBCs) in the maternal circulation while controls contained <0.10%. Placental findings associated with FMH were determined. Results In this study, 35 cases and 79 controls were identified. Villous dysmaturity/immaturity was significantly more prevalent among the cases compared to the controls. Placentas with villous edema and nucleated RBCs (nRBCs) in fetal vessels were associated with greater mean volumes of fetal blood in the maternal circulation. Fetal and maternal vascular pathology was more frequent in the controls. When the cases were stratified into mild (<30 mL), moderate (30 mL-100 mL), and severe (>100 mL) FMH, nRBCs, villous dysmaturity/immaturity, and villous edema were all positively correlated with increasing FMH severity. The cases were more likely than the controls to display ≥2 of these 3 features. Fetal nRBCs within fetal vessels were semi-quantified and moderate to severe numbers of nRBCs were associated with higher mean volumes of fetal blood in maternal circulation. Conclusions Villous dysmaturity/immaturity, villous edema, and nRBCs in fetal vessels, findings compatible with fetal anemia, in addition to relatively few chronic placental changes, are the most significant placental findings in FMH detected by flow cytometry.

Fetomaternal hemorrhage complicated pregnancy: risks, identification, and management

PURPOSE OF REVIEW

This article aims not only to review recent literature about the clinical features of massive fetomaternal hemorrhage (FMH) and identification of risk factors, but also to alert obstetricians and pediatricians to this underdiagnosed and underestimated severe obstetrical issue. In addition, a simplified flow chart for the antenatal management of suspected FMH is proposed.

RECENT FINDINGS

Improvements in obstetrical and neonatal care have decreased perinatal morbidity and mortality and the rate of stillbirth. Unfortunately, because of the nonspecific signs on presentation, adverse outcome associated with massive FMH has not followed this trend and still has devastating consequences. As even the definition varies among publications and there is lack of universal screening, the real nature still remains obscure. Improvements in the diagnosis of fetal anemia, laboratory and intrauterine transfusion techniques, and the implementation of prenatal and postnatal neuroprotection give some hope for the better outcome in the most severe cases. Unfortunately, obstetricians' awareness of the massive FMH remains still at an unacceptably low level.

SUMMARY

There is an urgent need for the internationally accepted definition, standardized pregnancy management protocol, and structured follow-up of neonates from such pregnancies. We suggest the international registry of massive FMH cases.

Pathology Consultation on Patients With a Large Rh Immune Globulin Dose Requirement

OBJECTIVES

To review the differential diagnosis and laboratory issues for women with a large calculated dose of Rh immune globulin (RhIG).

METHODS

A case-based approach is used to review the differential diagnosis of patients with a large calculated dose of RhIG, RhIG dosing for women with baseline elevations in hemoglobin F, the formulations of RhIG, and issues for the transfusion medicine service with the release of large doses of RhIG.

RESULTS

A large fetomaternal bleed after delivery requiring multiple doses of RhIG is rare. Such patients may require intravenous RhIG to avoid multiple injections. Patients with a large percentage of circulating fetal RBCs should be evaluated for a disorder of hemoglobin synthesis and, if present, should have quantification of the circulating fetal RBCs by flow cytometry.

CONCLUSIONS

Accurate laboratory evaluation of women with large fetomaternal bleeds is essential for appropriate RhIG administration.

Flow cytometry in hematological nonmalignant disorders

Multiparameter flow cytometry (MFC) has become an integral part of the diagnosis and classification of hematological malignancies. However, several nonmalignant or premalignant disorders may benefit from this technology in hematology laboratories. This review provides information on the normal immunophenotypic characteristics of peripheral blood leukocyte subsets and their modifications in several clinical conditions. The usefulness of MFC and the specific markers that can be investigated in hyperlymphocytosis, infection, hypereosinophilia, paroxysmal nocturnal hemoglobinuria, and large granular lymphocyte disorders is described. Mention is also made of the developments of MFC for analyses of red blood cells or platelets.

Pathology of the stillborn infant for the general pathologist: part 1

As the information obtained from previable fetal and stillbirth autopsies is used not only to explain the loss to the parents, but for future pregnancy planning, general pathologists need to be comfortable in dealing with these autopsies. The importance of an adequate fetal examination has been emphasized in a recent policy on the subject by the American Board of Pathology http://www.abpath.org/FetalAutopsyPolicy.pdf. This review paper covers the approach to the fetal and stillbirth autopsy. This first article covers the approach to the nonanomalous and anomalous autopsy. Hydrops fetalis will be covered in the second part of this series to be published subsequently.

Assessment of feto-maternal hemorrhage among rhesus D negative pregnant mothers using the kleihauer-betke test (KBT) and flow cytometry (FCM) in Addis Ababa, Ethiopia

BACKGROUND

This study aimed to assess fetomaternal hemorrhage (FMH) among RhD negative pregnant mothers using two techniques, Kleihauer-Betke (KBT) and Flow cytometry (FCM). To determine if patient-specific doses of prophylactic anti-D warrant further investigation in Ethiopia and wider Africa.

METHODS

Hospital- based cross-sectional study was conducted among 75 RhD negative pregnant mothers using convenient sampling technique.

RESULT

FMH has been detected in 52% and 60% by KBT and FCM techniques, respectively. The volume of FMH quantified in the majority of the cases (92.5% and 87%) was <10 mL fetal blood while >30 mL in 1.3% (1/75) and 2.7% (2/75) as calculated by KBT and FCM, respectively. The FMH calculated by the two methods have good correlation; r = 0.828 (p = 0.000) for categorized and r = 0.897 (p = 0.000) for continuous values and the agreement between the FCM and KBT was moderate with kappa (κ) value of 0.53 (p = 0.000).

CONCLUSION

Most of FMH calculated (<10 mL) could have been neutralized by lower doses which might have lower costs than administering 300 μg dose which is currently in practice in our country for affording mothers. Besides, it also showed that the volume of FMH was >30 mL in 1.3% and 2.7% of the cases as calculated by KBT and FCM, respectively, which need more than 300 μg dose RhIG for neutralization. Further investigation into the cost- effectiveness and scalability of patient- specific dosing of prophylactic anti-D appears warranted.

Placental and cord insertion pathologies: screening, diagnosis, and management

Placenta previa, low-lying placenta, and placenta accreta are aberrations in the normal development of the placenta. Diagnosis in the prenatal period is essential because each of these pathologies can have a profound impact on the management of labor, birth, and the third stage. In recent years, there has been an increase in the occurrence of these placental abnormalities, with the increase in the cesarean rate considered to be a main cause of this phenomenon. Comprehensive risk assessment, combined with recent advances in ultrasonography, can provide earlier detection of impaired placental implantation. Umbilical cord insertion pathologies are also of concern. Velamentous cord insertion is a defect in the insertion site of the umbilical cord resulting from the atrophy of portions of the developing placenta. In this condition, the blood vessels of the umbilical cord are not protected by Wharton's jelly, resulting in a potential for increased risk of breakage when the amniotic membranes rupture. Vasa previa is a velamentous insertion of the umbilical cord in which the blood vessels are present over the cervical os. If these blood vessels rupture during labor, it can have catastrophic effects on the fetus. Prenatal diagnosis of this condition can allow the certified nurse-midwife/certified midwife (CNM/CM) to plan for the safe birth of the newborn and avoid fetal hemorrhage. This article provides a review of risk factors, diagnosis pathophysiology, and management options for these conditions, thus enabling the CNM/CM to provide safe, effective care and management.

Benefits of delayed fetal hemoglobin (HbF) switching in sickle cell disease (SCD): a case report and review of the literature

Sickle cell disease is an autosomal recessive hemoglobinopathy with significant morbidity and mortality. Complications include: vasoocclusive pain crisis, bacterial infection, cerebral vascular accident, acute chest syndrome, and chronic lung and kidney disease. Among many other factors affecting the severity of sickle cell disease, synthesis of fetal hemoglobin (HbF) emerged as an important prognostic factor and has long been recognized to decrease disease severity. This report discusses the attenuated clinical course of a child who continued to produce HbF well beyond the reported age of fetal switching. We further discuss the underlying genetic aspects of HbF production and review the pertinent literature.

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

BACKGROUND

Complete automation of high-performance liquid chromatography (HPLC) for determination of hemoglobin F (%Hb F) and hemoglobin A1c (%Hb A1c) levels has made this procedure available in many clinical laboratories. However, the physiological changes in %Hb F during pregnancy and the effects of physiological and supraphysiological levels of %Hb A1c on measurement of %Hb F have not been studied extensively.

METHODS

Simultaneous determination of %Hb F and %Hb A1c was conducted in 490 blood samples obtained before (n=21), during the 1st (n=150), 2nd (n=116), and 3rd (n=192) trimesters of pregnancy, and postpartum (n=11) from 357 women, including 60 women with hyperglycemia but unaffected by clinical fetomaternal hemorrhage, by HPLC.

RESULTS

Mean (SD) Hb F levels were 0.71% (0.25%) before pregnancy. The value of 0.82% (0.47%) during the 1st trimester decreased significantly to 0.66% (0.35%) during the 2nd trimester and to 0.58% (0.38%) during the 3rd trimester. The level was 0.62% (0.31%) approximately one year after delivery. Thus, %Hb F was highest during the 1st trimester of pregnancy. The effects of varied %Hb A1c levels on %Hb F measurements were clinically negligible.

CONCLUSIONS

The data presented in this work may be used as reference intervals of %Hb F determined with HPLC during pregnancy.