The near disappearance of fetal hydrops in relation to current state-of-the-art management of red cell alloimmunization

Hemoglobin Electrophoresis versus Kleihauer-Betke to Determine Bone Marrow Suppression in Fetuses Undergoing Intrauterine Transfusion

OBJECTIVE

 Mainstay therapy for fetuses affected by maternal red cell alloimmunization is serial intrauterine transfusion (IUT). Testing to determine when fetal red cells have been replaced with donor cells historically involves the use of the Kleihauer-Betke (KB) test. Hemoglobin (Hgb) electrophoresis testing may be more rapid with a reduced cost of analysis. We aimed to determine the correlation between fetal Hgb electrophoresis versus the traditional KB test.

STUDY DESIGN

 This is a retrospective analysis of all alloimmunized singleton pregnancies undergoing IUT between January 1, 2021, and July 1, 2023. Maternal and fetal characteristics were collected along with the indication for IUT. A final fetal blood sample was obtained at the conclusion of each transfusion and sent for KB testing and Hgb electrophoresis. The primary outcome was the assessment of these parameters in their ability to predict the replacement of the fetal circulating red cell population with donor cells. Linear regression analysis and repeated measures analysis of variance were performed, and p-values less than 0.05 were considered significant.

RESULTS

 A total of 56 IUTs were performed in 16 patients. There were 39 (69.6%) final KB test values collected and compared with 30 (53.6%) final Hgb electrophoresis values. Hgb electrophoresis when compared with the KB test demonstrated a significant correlation (R 2 = 0.93; 95% confidence interval, 0.61-0.76; p < 0.001). This same finding held true when examining the correlation at each individual IUT as well. The final KB test and Hgb electrophoresis values significantly decreased with each transfusion (p = 0.003). A predominance of adult donor blood was noted by the third transfusion for both laboratory indices.

CONCLUSION

 Fetal Hgb electrophoresis obtained at the time of IUT demonstrates a significant correlation with the traditional KB test.

KEY POINTS

· Fetal Hgb electrophoresis following IUT is underexplored. · Hgb electrophoresis is an automated evaluation. · The traditional KB test is a manual evaluation. · These two tests demonstrate significant correlation.

Hemolytic disease of the fetus and newborn and Rhesus alloimmunization in Latin American countries: a scoping review

BACKGROUND

Hemolytic disease of the fetus and newborn (HDFN) is a condition due to maternal blood group antibodies targeting antigens in fetal red blood cells, with significant prenatal/perinatal morbidity and mortality. Severe HDFN cases are often associated with alloimmunization against Rhesus D (RhD) or Kell antigens. Information about HDFN epidemiology and treatment in Latin American countries is limited. This review aims to identify and synthesize the available evidence on the epidemiology and management of HDFN in this region.

METHODS

In July 2023, EMBASE, PubMed, LILACS, and other databases were searched for articles reporting epidemiology, treatment, prenatal and perinatal outcomes, and patient journey of HDFN cases in Latin American countries. A snowball search of cross-references and gray literature complemented the initial search. Publications in English, Spanish, and Portuguese were reviewed. Data were extracted using a defined template and charted in tables.

RESULTS

We reviewed five guidelines and 19 observational studies from Brazil, Chile, Mexico, Argentina, Colombia, Panamá, Paraguay, and Peru. HDFN due to Rh alloimmunization ranged from 0.5 to 5 per 1000 live births, and anti-D remains the most frequent alloantibody type for severe HDFN. The perinatal mortality rate of HDFN is approximately 1.3-1.6 per 100,000 live births, and fetal deaths can reach 30% among patients treated with intrauterine transfusions. Up to 47% of alloimmunized pregnancies were referred to reference centers only during the third trimester. About 60% of eligible pregnancies received anti-D IgG prophylaxis.

CONCLUSIONS

Although estimates in LATAM countries are scarce and lack standardized measures, we observed that the incidence, morbidity, and mortality of HDFN in this region are problematic. RhD alloimmunization was reported in approximately up to 70% of severe HDFN cases, despite anti D HDFN being largely preventable.

Variations in antenatal management and outcomes in haemolytic disease of the fetus and newborn: an international, retrospective, observational cohort study

BACKGROUND

Advances in haemolytic disease of the fetus and newborn have led to numerous treatment options. We report practice variations in the management and outcomes of haemolytic disease of the fetus and newborn in at-risk pregnancies.

METHODS

In this international, retrospective, observational cohort study, data from cases with moderate or severe haemolytic disease of the fetus and newborn were retrieved from 31 centres in 22 countries. Eligible participants had pregnancies with haemolytic disease of the fetus that led to fetal death at 16 + 0 weeks or later, those treated antenatally with intrauterine transfusion or intravenous immunoglobulins, or neonates without antenatal treatment who were treated with intensive phototherapy, exchange transfusion, or red blood cell transfusions. All patients had confirmed maternal alloantibodies and an antigen-positive fetus incompatible with the maternal alloantibody. Patients with ABO-incompatibility only were excluded. We assessed serological diagnostics and referrals, antenatal treatment and timing, complications, delivery route, and gestational age at birth. Outcomes were analysed in all eligible participants who had complete data available.

FINDINGS

2443 pregnancies with haemolytic disease of the fetus and newborn treated between Jan 1, 2006, and July 1, 2021, were shared by the centres and analysed between Dec 1, 2021, and March 1, 2023. 23 pregnancies were excluded due to missing information and we included 2420 for further analysis. 1764 (72·9%) of 2420 pregnancies were affected by D-antibodies. 95 (3·9%) of 2420 pregnancies resulted in fetal death. Of the 2325 liveborn neonates, 1349 (58·1%) received any form of antenatal treatment and 976 (41·9%) were only treated postnatally. Median gestational age at referral was 20·4 weeks (IQR 14·9-28·0) and ranged between medians of 10·0 and 26·3 weeks between centres. Severe hydrops at first intrauterine transfusion was present in 185 (14·5%) of 1276 pregnancies, with proportions ranging between 0 and 42% between centres. A median of two intrauterine transfusions (IQR 1-4) were done per pregnancy. The fetal access sites used in intrauterine transfusions varied widely between centres. Non-lethal complications in intrauterine transfusions by transfusion site occurred at a lower rate in intrahepatic approaches (2·0%, 95% CI 1·1-3·3) than in placental insertion (6·9%, 5·8-8·0) and free loop (13·3%, 8·9-18·9). The use and indication for intravenous immunoglobulin administration varied widely. Neonates with intrauterine transfusion were born at a median gestational age of 35·6 weeks (IQR 34·0-36·7), ranging between medians of 33·2 and 37·3 weeks between centres, while neonates without antenatal treatment were born at a median gestational age of 37·3 (IQR 36·3-38·1), ranging between medians of 34·9 and 38·9 weeks between centres.

INTERPRETATION

We found considerable variation in antenatal management and outcomes in haemolytic disease of the fetus and newborn between sites in different countries. Our study shows the capacity of the field to gather valuable data on a rare disease and to optimise care.

FUNDING

None.

Economic analysis of foregoing Rh immunoglobulin for bleeding in pregnancy <12 weeks gestation

OBJECTIVES

To perform cost analyses of foregoing RhD blood type testing and administration of Rh immunoglobulin (RhIg) for bleeding in pregnancy at <12 weeks gestation in the United States.

STUDY DESIGN

We created a decision-analytic model comparing the current standard treatment pathway for patients who have threatened, spontaneous, or induced abortion in the United States, with a new pathway foregoing RhD testing and administration of RhIg for those who are RhD-negative at <12 weeks gestation, assuming that the risk of sensitization is 0%. We derived population and cost estimates from the current literature and calculated the number needed to treat (NNT) and number needed to screen to avoid one case of fatal hemolytic disease of the fetus and newborn. We performed sensitivity analyses assuming Rh-sensitization risks of 1.5% and 3% and varying the subsequent pregnancy rates from 44% to 100%.

RESULTS

The annual savings to health care payers in the United States of foregoing RhD testing and RhIg administration with bleeding events at <12 weeks are $5.5 million/100,000 total pregnancies, assuming the sensitization risk is 0%. In sensitivity analyses with a sensitization risk of 1.5% and subsequent pregnancy rate of 84.3% foregoing Rh testing and RhIg administration would save $2.8 million/100,000 pregnancies, with a NNT of 7322 and a number needed to screen of 48,816. At a 3% sensitization rate, the current standard treatment pathway is most economical.

CONCLUSIONS

There is an opportunity to save as much as $5.5 million/100,000 pregnancies by withholding RhIg in specific situations and conserving it for use later in pregnancy.

IMPLICATIONS

Cost analyses support foregoing RhD blood type screening and RhIg administration at <12 weeks gestation if the sensitization rate is <3%. By deimplementing this low-value care, payers in the United States can save as much as $5.5 million/100,000 pregnancies and conserve RhIg for use later in pregnancy.

Perceived Impact of Healthcare Relationships and Interactions on Parental Experiences of Prenatal Diagnosis and Termination of Pregnancy for Foetal Anomaly on the Island of Ireland

OBJECTIVE

The aim of this study was to explore parents' experiences of their relationships and interactions with healthcare professionals (HCPs) during care related to prenatal diagnosis and termination of pregnancy for foetal anomaly (TOPFA).

METHODS

A qualitative approach was used. Participants included 33 parents (23 women and 10 men) from Northern Ireland (n = 11) and Ireland (n = 22) who had a TOPFA. Data collection methods included semi-structured interviews and written narrative accounts. Data were analysed using thematic analysis.

RESULTS

Findings confirmed that TOPFA was a traumatic, life-altering experience for parents, impacting their health and well-being. The actions, behaviours and words of HCPs impacted how parents perceived and interpreted their healthcare experiences and their access to services and supports. In relation to this, five themes are presented: (1) the importance of compassionate and non-judgemental care, (2) the value of effective information and communication, (3) the desire for compassionate care for baby and facilitation of memory making, (4) the need for continuity of care and (5) parents' experiences of healthcare relationships during times of legislative change.

CONCLUSION

This research reveals the important role HCPs play in helping parents cope with prenatal testing and TOPFA. Parents who had a positive relationship with an HCP, in which information was communicated effectively and compassionate and non-judgmental care was provided, felt more supported and more able to accept and adapt to their loss.

PATIENT AND PUBLIC CONTRIBUTION

An advisory group composed of parents who had experienced TOPFA and HCPs with experience in caring for such families were involved in the study from the outset, contributing to the design and development of data collection materials, interpretation of the findings and design of dissemination materials.

Intravenous immunoglobulin for the treatment of severe maternal alloimmunization: individual patient data meta-analysis

OBJECTIVE

This study aimed to investigate the outcomes associated with the administration of maternal intravenous immunoglobulin in high-risk red blood cell-alloimmunized pregnancies.

DATA SOURCES

Medline, Embase, and Cochrane Library were systematically searched until June 2023.

STUDY ELIGIBILITY CRITERIA

This review included studies reporting on pregnancies with severe red blood cell alloimmunization, defined as either a previous fetal or neonatal death or the need for intrauterine transfusion before 24 weeks of gestation in the previous pregnancy as a result of hemolytic disease of the fetus and newborn.

METHODS

Cases were pregnancies that received intravenous immunoglobulin, whereas controls did not. Individual patient data meta-analysis was performed using the Bayesian framework.

RESULTS

Individual patient data analysis included 8 studies consisting of 97 cases and 97 controls. Intravenous immunoglobulin was associated with prolonged delta gestational age at the first intrauterine transfusion (gestational age of current pregnancy - gestational age at previous pregnancy) (mean difference, 3.19 weeks; 95% credible interval, 1.28-5.05), prolonged gestational age at the first intrauterine transfusion (mean difference, 1.32 weeks; 95% credible interval, 0.08-2.50), reduced risk of fetal hydrops at the time of first intrauterine transfusion (incidence rate ratio, 0.19; 95% credible interval, 0.07-0.45), reduced risk of fetal demise (incidence rate ratio, 0.23; 95% credible interval, 0.10-0.47), higher chances of live birth at ≥28 weeks (incidence rate ratio, 1.88; 95% credible interval, 1.31-2.69;), higher chances of live birth at ≥32 weeks (incidence rate ratio, 1.93; 95% credible interval, 1.32-2.83), and higher chances of survival at birth (incidence rate ratio, 1.82; 95% credible interval, 1.30-2.61). There was no substantial difference in the number of intrauterine transfusions, hemoglobin level at birth, bilirubin level at birth, or survival at hospital discharge for live births.

CONCLUSION

Intravenous immunoglobulin treatment in pregnancies at risk of severe early hemolytic disease of the fetus and newborn seems to have a clinically relevant beneficial effect on the course and severity of the disease.

A challenging case of hemolytic disease of the fetus and newborn (HDFN) due to anti-Ku in a K0 (Kellnull) mother

Hemolytic disease of the fetus and newborn (HDFN) due to an antibody in the Kell blood group system can be associated with severe fetal anemia. This case report details the challenges of managing a Kellnull mother with anti-Ku that affected her fetus/newborn. A gravida 4 para 3 woman at term underwent an emergency lower caesarean section because of fetal distress. The baby was intubated because of low oxygen saturation. An urgent request for a hematology workup showed severe anemia and erythroblastosis fetalis. Unfortunately, no compatible blood was found, and the baby died. The case was referred to the National Blood Centre, and anti-Ku was confirmed in a sample sent from the mother. When she presented with her fifth pregnancy, meticulous planning was used to manage this pregnancy. Her family screening revealed one brother with a matching phenotype. Three blood donations were planned for the brother-for freezing, for intrauterine transfusion, and for standby during delivery. Serial anti-Ku titrations of maternal samples were performed, and the fetus was monitored for anemia through middle cerebral artery Doppler scans. Although the anti-Ku titers reached as high as 1024, fetal anemia was never diagnosed. The neonate was delivered safely but was diagnosed with severe pathologic jaundice and anemia secondary to HDFN and congenital pneumonia. The baby was transfused with K0 packed red blood cells and later discharged to home.

The Efficacy of Low-Titer Group O Whole Blood Compared With Component Therapy in Civilian Trauma Patients: A Meta-Analysis

OBJECTIVES

To assess if transfusion with low-titer group O whole blood (LTOWB) is associated with improved early and/or late survival compared with component blood product therapy (CT) in bleeding trauma patients.

DATA SOURCES

A systematic search of PubMed, CINAHL, and Web of Science was performed from their inception through December 1, 2023. Key terms included injury, hemorrhage, bleeding, blood transfusion, and whole blood.

STUDY SELECTION

All studies comparing outcomes in injured civilian adults and children who received LTOWB versus CT were included.

DATA EXTRACTION

Data including author, publication year, sample size, total blood volumes, and clinical outcomes were extracted from each article and reported following the Meta-analysis Of Observational Studies in Epidemiology guidelines. Main outcomes were 24-hour (early) and combined 28-day, 30-day, and in-hospital (late) mortality rates between recipients of LTOWB versus CT, which were pooled using random-effects models.

DATA SYNTHESIS

Of 1297 studies reviewed, 24 were appropriate for analysis. Total subjects numbered 58,717 of whom 5,164 received LTOWB. Eleven studies included adults-only, seven included both adults and adolescents, and six only included children. The median (interquartile range) age for patients who received LTOWB and CT was 35 years (24-39) and 35.5 years (23-39), respectively. Overall, 14 studies reported early mortality and 22 studies reported late mortality. LTOWB was associated with improved 24-hour survival (risk ratios [RRs] [95% CI] = 1.07 [1.03-1.12]) and late (RR [95% CI] = 1.05 [1.01-1.09]) survival compared with component therapy. There was no evidence of small study bias and all studies were graded as a moderate level of bias.

CONCLUSIONS

These data suggest hemostatic resuscitation with LTOWB compared with CT improves early and late survival outcomes in bleeding civilian trauma patients. The majority of subjects were injured adults; multicenter randomized controlled studies in injured adults and children are underway to confirm these findings.

Management Considerations for Air Medical Transport Programs Transfusing RhD-Positive Red Blood Cell-Containing Products to Females of Childbearing Potential

Recent years have seen increased discussion surrounding the benefits of damage control resuscitation, prehospital transfusion (PHT) of blood products, and the use of whole blood over component therapy. Concurrent shortages of blood products with the desire to provide PHT during air medical transport have prompted reconsideration of the traditional approach of administering RhD-negative red cell-containing blood products first-line to females of childbearing potential (FCPs). Given that only 7% of the US population has blood type O negative and 38% has O positive, some programs may be limited to offering RhD-positive blood products to FCPs. Adopting the practice of giving RhD-positive blood products first-line to FCPs extends the benefits of PHT to such patients, but this practice does incur the risk of future hemolytic disease of the fetus and newborn (HDFN). Although the risk of future fetal mortality after an RhD-incompatible transfusion is estimated to be low in the setting of acute hemorrhage, the number of FCPs who are affected by this disease will increase as more air medical transport programs adopt this practice. The process of monitoring and managing HDFN can also be time intensive and costly regardless of the rates of fetal mortality. Air medical transport programs planning on performing PHT of RhD-positive red cell-containing products to FCPs should have a basic understanding of the pathophysiology, prevention, and management of hemolytic disease of the newborn before introducing this practice. Programs should additionally ensure there is a reliable process to notify receiving centers of potentially RhD-incompatible PHT because alloimmunization prophylaxis is time sensitive. Facilities receiving patients who have had PHT must be prepared to identify, counsel, and offer alloimmunization prophylaxis to these patients. This review aims to provide air medical transport professionals with an understanding of the pathophysiology and management of HDFN and provide a template for the early management of FCPs who have received an RhD-positive red cell-containing PHT. This review also covers the initial workup and long-term anticipatory guidance that receiving trauma centers must provide to FCPs who have received RhD-positive red cell-containing PHT.

Disease severity in subsequent pregnancies with RhD immunization: A nationwide cohort

BACKGROUND AND OBJECTIVES

To evaluate the severity of haemolytic disease of the foetus and newborn (HDFN) in subsequent pregnancies with RhD immunization and to identify predictive factors for severe disease.

MATERIALS AND METHODS

Nationwide prospective cohort study, including all pregnant women with RhD antibodies. All women with at least two pregnancies with RhD antibodies and RhD-positive foetuses were selected. The main outcome measure was the severity of HDFN in the first and subsequent pregnancy at risk. A subgroup analysis was performed for the group of women where RhD antibodies developed after giving birth to an RhD-positive child and thus after receiving anti-D at least twice (group A) or during the first pregnancy at risk for immunization (group B).

RESULTS

Sixty-two RhD immunized women with a total of 150 RhD-positive children were included. The severity of HDFN increased for the whole group significantly in the subsequent pregnancy (p < 0.001), although it remained equal or even decreased in 44% of women. When antibodies were already detected at first trimester screening in the first immunized pregnancy, after giving birth to an RhD-positive child (group A), severe HDFN in the next pregnancy was uncommon (22%). Especially when no therapy or only non-intensive phototherapy was indicated during the first immunized pregnancy (6%) or if the antibody-dependent cell-mediated cytotoxicity result remained <10%. Contrarily, women with a negative first trimester screening and RhD antibodies detected later during the first pregnancy of an RhD-positive child (group B), often before they had ever received anti-D prophylaxis, were most prone for severe disease in a subsequent pregnancy (48%).

CONCLUSION

RhD-mediated HDFN in a subsequent pregnancy is generally more severe than in the first pregnancy at risk and can be estimated using moment of antibody detection and severity in the first immunized pregnancy. Women developing antibodies in their first pregnancy of an RhD-positive child are at highest risk of severe disease in the next pregnancy.

Maternal and child life years gained by transfusing low titer group O whole blood in trauma: A computer simulation

BACKGROUND

Using low titer group O whole blood (LTOWB) is increasingly popular for resuscitating trauma patients. LTOWB is often RhD-positive, which might cause D-alloimmunization and hemolytic disease of the fetus and newborn (HDFN) if transfused to RhD-negative females of childbearing potential (FCP). This simulation determined the number of life years gained by the FCP and her future children if she was resuscitated with LTOWB compared with conventional component therapy (CCT).

METHODS

The model simulated 500,000 injured FCPs of each age between 0 and 49 years with LTOWB mortality relative reductions (MRRs) compared with components between 0.1% and 25%. For each surviving FCP, number of life years gained was calculated using her age at injury and average life expectancy for American women. The number of expected future pregnancies for FCPs that did not survive was also based on her age at injury; each future child was assigned the maximum lifespan unless they suffered perinatal mortality or serious neurological events from HDFN.

RESULTS

The LTOWB group with an MRR 25% compared with CCT had the largest total life years gained. The point of equivalence for RhD-positive LTOWB compared to CCT, where life years lost due to severe HDFN was equivalent to life years gained due to FCP survival/future childbearing, occurred at an MRR of approximately 0.1%.

CONCLUSION

In this model, RhD-positive LTOWB resulted in substantial gains in maternal and child life years compared with CCT. A >0.1% relative mortality reduction from LTOWB offset the life years lost to HDFN mortality and severe neurological events.

Severity of haemolytic disease of the fetus and newborn in patients with a history of intrauterine transfusions in a previous pregnancy: A nationwide retrospective cohort study

OBJECTIVE

Pregnant women who received at least one intrauterine transfusion (IUT) for haemolytic disease of the fetus and newborn (HDFN) in the preceding pregnancy are presumed to have a high likelihood of requiring IUTs again, often starting at an earlier gestational age. Our aim was to quantify these risks in a large national cohort.

DESIGN

Retrospective cohort study of a nationwide Dutch database.

SETTING

The Netherlands.

POPULATION

All women treated in The Netherlands with IUTs for Rhesus D (RhD)- or Kell-mediated HDFN between 1999 and 2017 and their follow-up pregnancies were included. Pregnancies with an antigen-negative fetus were excluded.

METHODS

Electronic patient files were searched for the number and gestational age of each IUT, and analysed using descriptive statistics and linear regression.

MAIN OUTCOME MEASURES

Percentage of women requiring one or more IUTs again in the subsequent pregnancy, and gestational age at first IUT in both pregnancies.

RESULTS

Of the 321 women in our study population, 21% (69) had a subsequent ongoing pregnancy at risk. IUTs were administered in 86% (59/69) of cases. In subsequent pregnancies, the median gestational age at first IUT was 3 weeks earlier (interquartile range -6.8 to 0.4) than in the preceding pregnancy.

CONCLUSIONS

Our study shows that pregnant women with a history of IUTs in the previous pregnancy are highly likely to require IUTs again, and on average 3 weeks earlier. Clinicians need to be aware of these risks and ensure timely referral, and close surveillance from early pregnancy onwards. Additionally, for women with a history of IUT and their caregivers, this information is essential to enable adequate preconception counselling.

The selection and preparation of red cell components for intrauterine transfusion: A national survey

BACKGROUND AND OBJECTIVES

The practice regarding the selection and preparation of red blood cells (RBCs) for intrauterine transfusion (IUT) is variable reflecting historical practice and expert opinion rather than evidence-based recommendations. The aim of this survey was to assess Canadian hospital blood bank practice with respect to red cell IUT.

MATERIALS AND METHODS

A survey was sent to nine hospital laboratories known to perform red cell IUT. Questions regarding component selection, processing, foetal pre-transfusion testing, transfusion administration, documentation and traceability were assessed.

RESULTS

The median annual number of IUTs performed in Canada was 109 (interquartile range, 103-118). RBC selection criteria included allogeneic, Cytomegalovirus seronegative, irradiated, fresh units with most sites preferentially providing HbS negative, group O, RhD negative, Kell negative and units lacking the corresponding maternal antibody without extended matching to the maternal phenotype. Red cell processing varied with respect to target haematocrit, use of saline reconstitution (n = 4), use of an automated procedure for red cell concentration (n = 1) and incorporation of a wash step (n = 2). Foetal pre-transfusion testing uniformly included haemoglobin measurement, but additional serologic testing varied. A variety of strategies were used to link the IUT event to the neonate post-delivery, including the creation of a unique foetal blood bank identifier at three sites.

CONCLUSION

This survey reviews current practice and highlights the need for standardized national guidelines regarding the selection and preparation of RBCs for IUT. This study has prompted a re-examination of priorities for RBC selection for IUT and highlighted strategies for transfusion traceability in this unique setting.

Intrauterine Transfusion for Rhesus Alloimmunization: A Historical Retrospective Cohort from A Single Reference Center in Brazil

Objective: This study aimed to describe the historical experience of a single reference center in Brazil with intrauterine transfusion (IUT) for Rhesus (Rh) alloimmunization, evaluating the major complications and the perinatal outcomes of this procedure. Methods: This retrospective cohort study evaluated data from medical records of pregnant women between 20 and 34 weeks of gestation whose fetuses underwent IUT by cordocentesis between January 1991 and June 2021. The same experienced examiner performed all procedures. Univariate and multivariate logistic regression was used to assess the effect of fetal hydrops, duration of IUT, post-transfusion cord bleeding time, and bradycardia on death (fetal or neonatal). Results: We analyzed data from 388 IUTs in 169 fetuses of alloimmunized pregnant women with a mean age of 29.3 ± 5.1 years. Death and fetal hydrops were significantly associated at first IUT (p < 0.001). We had two cases of emergency cesarean section (mean of 0.51% per IUT) and three cases of premature rupture of the ovular membranes (mean of 0.77% per procedure). Thirty-six deaths were recorded, including 14 intrauterine and 22 neonatal. A higher percentage of neonatal deaths was observed in the group with post-transfusion cord bleeding time > 120 s (45.8%). The odds of neonatal death were 17.6 and 12.9 times higher in cases with hydrops and bradycardia than in cases without hydrops and bradycardia, respectively. The odds of death (fetal and neonatal) were 79.9 and 92.3 times higher in cases with hydrops and bradycardia than in cases without hydrops and bradycardia, respectively. Conclusions: The most common complications of IUT for Rh alloimmunization were post-transfusion cord bleeding, fetal bradycardia, premature rupture of ovular membranes, and emergency cesarean section. The IUT complication most associated with death (fetal and neonatal) was bradycardia, and the perinatal outcomes were worse in fetuses with hydrops.

Another piece of the hemolytic disease of the fetus and newborn puzzle after RhD-positive transfusion in trauma resuscitation: the proportion of pregnant women who produce high titer anti-D

Background

After the transfusion of RhD-positive red blood cell (RBC)-containing products to an RhD-negative woman of childbearing potential (WCP) during trauma resuscitation, there are several events that must occur for that WCP to have a future pregnancy affected by hemolytic disease of the fetus and newborn (HDFN). This study identified and quantitated the frequency of a novel event in the sequence from RhD-positive transfusion during trauma resuscitation to an HDFN outcome, that is, the development of a high titer anti-D among women who were D-alloimmunized.

Methods

The transfusion service records at one maternity hospital were searched to locate all anti-D titers that had been performed on pregnant women between 1996 and 2022. The highest titer score during each pregnancy was recorded for this study. The critical titer threshold at this institution was ≥16. Passive anti-D caused by Rh immunoglobulin were excluded from analysis.

Results

There were 97 pregnancies in 85 patients who had an immune-stimulated anti-D; in 60 of 97 (62%) pregnancies, the highest titer score was ≥16. There were 12 patients who had titers performed in two pregnancies during the study period; the correlation between the maximum titer in each pregnancy was not statistically significant (Spearman rank correlation r=0.42, p=0.17).

Conclusion

In this single center study, 62% of D-alloimmunized pregnant women had a high titer antibody. When considering all of the events that must occur for HDFN to happen, the rate of perinatal mortality was calculated to be 0.04% and the rate of perinatal death or serious adverse event from HDFN was 0.24%.

The females have spoken: A patient-centered national survey on the administration of emergent transfusions with the potential for future fetal harm

BACKGROUND

Traumatic hemorrhage is the leading cause of preventable death. Early in the resuscitation, only RhD-positive red blood cells are likely to be available, which poses a small risk of causing harm to a future fetus if transfused to an RhD-negative females of childbearing age (CBA), that is, 15 to 49 years old. We sought to characterize how the population, in particular females of CBA, felt about emergency blood administration vis-a-vis potential future fetal harm.

METHODS

A national survey was performed using Facebook advertisements in three waves from January 2021 to January 2022. The advertisements directed users to the survey site with seven demographic questions and four questions on accepting transfusion with differing probabilities for future fetal harm (none/any/1:100/1:10,000). Acceptance of transfusion questions were scored on 3-point Likert scale (likely/neutral/unlikely). Only completed responses by females were analyzed.

RESULTS

Advertisements were viewed 16,600,430 times by 2,169,805 people with 15,396 advertisement clicks and 2,873 surveys initiated. Most (2,256 of 2,873 [79%]) were fully completed. Majority (2,049 of 2,256 [90%]) of respondents were female. Eighty percent of females (1,645 of 2,049) were of CBA. Most females responded "likely" or "neutral" when asked whether they would accept a lifesaving transfusion if the following risk of fetal harm were present: no risk (99%), any risk (83%), 1:100 risk (85%), and 1:10,000 risk (92%). There were no differences between females of CBA versus non-CBA with respect to the likelihood of accepting lifesaving transfusion with any potential for future fetal harm ( p = 0.24).

CONCLUSION

This national survey suggests that most females would accept lifesaving transfusion even with the potential low risk of future fetal harm.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Immunohaematological conundrums in obstetrics from transfusion services viewpoint in Armed Forces setup

Background

Obstetrics as a speciality has a very long association with the transfusion services and poses its own set of immunohematological (IHL) challenges. A study was carried out to evaluate the spectrum of IHL issues in obstetrics in our setup and to suggest a way forward.

Methods

This study was carried out in a transfusion services setup catering to antenatal care (ANC) clientele in two tertiary-level health care setups. Samples were collected from all ANC patients requiring transfusion and patients reporting for Indirect Coombs Test (ICT). Data included ICT positive cases with implicated alloantibodies, those requiring specialised procedures and the foetal outcome. The results were described using descriptive statistics by frequencies and percentages.

Results

A total of 4683 eligible samples were included in the study, out of 21,893 antenatal patients visiting our setup during study period. One hundred thirty-six ANC patient samples were found to be ICT positive. The most common single alloantibody was anti-D (n = 77, 57.5%). Double antibody positivity was found in 28 patients. Multiple alloantibodies were found in 1 patient. Up to 48% of these allo-anti D cases necessitated specialised procedures.

Conclusion

The IHL issues of obstetrics faced in our setup are no less than that in Indian population. We have much higher frequency of double alloantibody in our ANC population. The authors propose that all multiparous ANC patients, especially with a history of transfusion, irrespective of Rh D status should be screened for irregular alloantibodies to circumvent these issues and the last-minute rush for provision of compatible units.

Hemolytic disease of the fetus and newborn: systematic literature review of the antenatal landscape

BACKGROUND

Prevention of pregnancy-related alloimmunization and the management of hemolytic disease of the fetus and newborn (HDFN) has significantly improved over the past decades. Considering improvements in HDFN care, the objectives of this systematic literature review were to assess the prenatal treatment landscape and outcomes of Rh(D)- and K-mediated HDFN in mothers and fetuses, to identify the burden of disease, to identify evidence gaps in the literature, and to provide recommendations for future research.

METHODS

We performed a systematic search on MEDLINE, EMBASE and clinicaltrials.gov. Observational studies, trials, modelling studies, systematic reviews of cohort studies, and case reports and series of women and/or their fetus with HDFN caused by Rhesus (Rh)D or Kell alloimmunization. Extracted data included prevalence; treatment patterns; clinical outcomes; treatment efficacy; and mortality.

RESULTS

We identified 2,541 articles. After excluding 2,482 articles and adding 1 article from screening systematic reviews, 60 articles were selected. Most abstracted data were from case reports and case series. Prevalence was 0.047% and 0.006% for Rh(D)- and K-mediated HDFN, respectively. Most commonly reported antenatal treatment was intrauterine transfusion (IUT; median frequency [interquartile range]: 13.0% [7.2-66.0]). Average gestational age at first IUT ranged between 25 and 27 weeks. weeks. This timing is early and carries risks, which were observed in outcomes associated with IUTs. The rate of hydrops fetalis among pregnancies with Rh(D)-mediated HDFN treated with IUT was 14.8% (range, 0-50%) and 39.2% in K-mediated HDFN. Overall mean ± SD fetal mortality rate that was found to be 19.8%±29.4% across 19 studies. Mean gestational age at birth ranged between 34 and 36 weeks.

CONCLUSION

These findings corroborate the rareness of HDFN and frequently needed intrauterine transfusion with inherent risks, and most births occur at a late preterm gestational age. We identified several evidence gaps providing opportunities for future studies.

Immunomodulation for early-onset haemolytic disease of the fetus/newborn: Can we delay the need for intrauterine transfusions?

When cases of severe fetal anaemia due to maternal red-cell alloimmunization present in the early second trimester, standard treatment with intrauterine transfusion often results in fetal loss. The report by Vlachodimitropoulou et al. offers new insight into the use of maternal intravenous immune globulin to delay the need for intrauterine transfusion. Performing these procedures at a later gestational age increases the likelihood of technical success and subsequent perinatal survival. Commentary on: Vlachodimitropoulou et al. Intravenous immune globulin in the management of severe early onset of red cell alloimmunization. Br J Haematol 2023; 200:97-103.

Practice patterns amongst fetal centers performing intrauterine transfusions (PACT): An international survey study

OBJECTIVES

Fetal anemia secondary to incompatibility between maternal-fetal blood types can result in hydrops and demise. Intrauterine transfusions have improved survival in experience centers. Our objective was to determine the practice patterns amongst fetal centers.

STUDY DESIGN

Thirteen fetal centers across the world were surveyed. Results from all participating centers were recorded, analyzed, and presented as ratios. Questions on the survey were related to experience of the physician, preferred methods of transfusion, fetal surveillance, and timing of delivery.

RESULTS

Differences amongst centers were as follows: 54% of the centers performed transfusions in operating room, the remaining did them in a clinic room or close to the operating room; 31% did not use maternal anesthesia, 31% used oral or intravenous sedation and 38% used a combination of local with oral or intravenous sedation. The similarities include: 84% performed intravenous transfusions, while 2 centers reported intraperitoneal and intracardiac transfusions were performed for very early cases; 85% of centers performed the last transfusion at 34-35 weeks and 77% electively delivered their patients at 37 weeks.

CONCLUSION

Method of transfusion and delivery timing was similar in most centers; however, differences were seen in location of procedure, anesthetic coverage, and surveillance. Further assessment is needed to determine if these differences in practice have any potential neonatal effects.

Attitudes of American adult women toward accepting RhD-mismatched transfusions in bleeding emergencies

BACKGROUND

There is an increasing literature demonstrating the benefits of prehospital and early in-hospital transfusions. RhD-positive products might only be available during these phases, which could pose consequences for future pregnancies if D-alloimmunization occurs. This survey measured the willingness of females to accept urgent but incompatible transfusions in light of the potential for future pregnancy complications.

METHODS

A survey was designed to assess the willingness of females ≥18 years of age to accept urgent incompatible transfusions when different absolute risk reductions in maternal mortality were presented along with a static rate of 0.3%-4.0% risk of harm to future pregnancies. The survey was sent electronically to women who are part of the Washington University Research Enhancement Core database.

RESULTS

A total of 4896 delivered survey email invitations were distributed and 325 (6.6%) responses were received; 16 responses were excluded leaving 309 responses for analysis. Most of the responding women were White, college-educated, and lived in Missouri. At least 90% of the respondents would accept an urgent incompatible transfusion when the absolute risk reduction in maternal mortality was ≥4%. Women without a college degree, who lived in Illinois, who were not able to have children appeared to be less willing than their counterparts to receive an incompatible transfusion when the absolute risk reduction in maternal mortality was low.

CONCLUSION

This survey demonstrated that adult women are highly likely to be open to accept urgent incompatible blood transfusions during a bleeding emergency when the absolute risk reduction in maternal mortality was ≥4%.

Rate of D-alloimmunization in trauma does not depend on the number of RhD-positive units transfused: The BEST collaborative study

BACKGROUND

Evidence indicates the life-saving benefits of early blood product transfusion in severe trauma resuscitation. Many of these products will be RhD-positive, so understanding the D-alloimmunization rate is important.

METHODS

This was a multicenter, retrospective study whereby injured RhD-negative patients between 18-50 years of age who received at least one unit of RhD-positive red blood cells (RBC) or low titer group O whole blood (LTOWB) during their resuscitation between 1 January, 2010 through 31 December, 2019 were identified. If an antibody detection test was performed ≥14 days after the index RhD-positive transfusion then basic demographic information was collected, including whether the patient became D-alloimmunized. The overall D-alloimmunization rate, and the rate stratified by the number of units transfused, were calculated.

RESULTS

Data were collected from nine institutions. Five institutions reported fewer than 10 eligible patients each and were excluded. From the remaining four institutions, all from the USA, there were 235 eligible patients; 77 (random effects estimate: 32.7%; 95% CI: 19.1-50.1%) became D-alloimmunized. Three of the institutions reported D-alloimmunization rates ≥38.6%, while the remaining institution's rate was 12.2%. In both random and fixed-effects models, the rate of D-alloimmunization was not significantly different between those who received one RhD-positive unit and those who received multiple RhD-positive units.

CONCLUSION

In this large, multicenter study of injured patients, the overall rate of D-alloimmunization fell within the range previously reported. The rate of D-alloimmunization did not increase as the number of transfused RhD-positive units increased. These data can help to inform RhD type selection decisions.

Termination of pregnancy for fetal anomaly: a systematic review of the healthcare experiences and needs of parents

BACKGROUND

Improved technology and advances in clinical testing have resulted in increased detection rates of congenital anomalies during pregnancy, resulting in more parents being confronted with the possibility of terminating a pregnancy for this reason. There is a large body of research on the psychological experience and impact of terminating a pregnancy for fetal anomaly. However, there remains a lack of evidence on the holistic healthcare experience of parents in this situation. To develop a comprehensive understanding of the healthcare experiences and needs of parents, this systematic review sought to summarise and appraise the literature on parents' experiences following a termination of pregnancy for fetal anomaly.

REVIEW QUESTION

What are the healthcare experiences and needs of parents who undergo a termination of pregnancy following an antenatal diagnosis of a fetal anomaly?

METHODS

A systematic review was undertaken with searches completed across six multi-disciplinary electronic databases (Medline, Embase, PsycINFO, CINAHL, Web of Science, and Cochrane). Eligible articles were qualitative, quantitative or mixed methods studies, published between January 2010 and August 2021, reporting the results of primary data on the healthcare experiences or healthcare needs in relation to termination of pregnancy for fetal anomaly for either, or both parents. Findings were synthesised using Thematic Analysis.

RESULTS

A total of 30 articles were selected for inclusion in this review of which 24 were qualitative, five quantitative and one mixed-methods. Five overarching themes emerged from the synthesis of findings: (1) Contextual impact on access to and perception of care, (2) Organisation of care, (3) Information to inform decision making, (4) Compassionate care, and (5) Partner experience.

CONCLUSION

Compassionate healthcare professionals who provide non-judgemental and sensitive care can impact positively on parents' satisfaction with the care they receive. A well organised and co-ordinated healthcare system is needed to provide an effective and high-quality service.

TRIAL REGISTRATION

PROSPERO registration number: CRD42020175970 .

Maternal bleeding complications in pregnancies affected by red blood cell alloimmunization

OBJECTIVE

To investigate whether women with red blood cell (RBC)¹ alloimmunization are more likely to experience bleeding complications during pregnancy or delivery than women without RBC alloimmunization.

STUDY DESIGN

Retrospective study involving all singleton pregnancies affected by RBC alloimmunization and without pre-existing maternal bleeding disorders or placenta previa, from 1 July 1999 to 30 June 2019 ("cases"). Only bleedings not related to invasive procedures (amnio- or cordocenteses) were included. Patients who were already at increased risk of pre- or perinatal bleeding due to their medical history (pre-existing bleeding disorders, antithrombotic therapy), or known obstetrics parameters (placental abnormalities etc.) were not included a priori. Cases were compared to controls without RBC alloimmunization, matched for maternal age and body mass index, from the same tertiary referral center in Austria.

RESULTS

130 cases were compared to 130 controls. Cases had significantly more previous pregnancies and miscarriages and their newborns had lower birthweight and were more often transferred to the intensive care unit than newborns of controls. 18/130 (13.8%) cases, compared to 8/130 (6.2%) controls experienced any bleeding during pregnancy or delivery (p = 0.061). Bleeding most often happened during the third trimester (cases: 4.6% vs. controls 0.8%, p = 0.12) and during or after delivery (cases: 7.7% vs. controls: 4.6%, p = 0.168). Binary logistic regression for the prediction of any bleeding complication during pregnancy, delivery or postpartum revealed immunization against RBC antigens as the only independent contributor (p = 0.04). Age, smoking, or previous obstetric history had no influence on the likelihood of maternal bleeding complications. Neither RBC antibody specificity nor titers were predictive of maternal bleeding during pregnancy or delivery.

CONCLUSION

Pregnancies affected by RBC alloimmunization might be at increased risk of maternal bleeding complications during pregnancy and delivery.

Risk factors for RhD immunisation in a high coverage prevention programme of antenatal and postnatal RhIg: a nationwide cohort study

OBJECTIVE

To evaluate which risk factors for RhD immunisation remain, despite adequate routine antenatal and postnatal RhIg prophylaxis (1000 IU RhIg) and additional administration of RhIg. The second objective was assessment of the current prevalence of RhD immunisations.

DESIGN

Prospective cohort study.

SETTING

The Netherlands.

POPULATION

Two-year nationwide cohort of alloimmunised RhD-negative women.

METHODS

RhD-negative women in their first RhD immunised pregnancy were included for risk factor analysis. We compared risk factors for RhD immunisation, occurring either in the previous non-immunised pregnancy or in the index pregnancy, with national population data derived from the Dutch perinatal registration (Perined).

RESULTS

In the 2-year cohort, data from 193 women were eligible for analysis. Significant risk factors in women previously experiencing a pregnancy of an RhD-positive child (n = 113) were: caesarean section (CS) (OR 1.7, 95% CI 1.1-2.6), perinatal death (OR 3.5, 95% CI 1.1-10.9), gestational age >42 weeks (OR 6.1, 95% CI 2.2-16.6), postnatal bleeding (>1000 ml) (OR 2.0, 95% CI 1.1-3.6), manual removal of the placenta (MRP) (OR 4.3, 95% CI 2.0-9.3); these factors often occurred in combination. The miscarriage rate was significantly higher than in the Dutch population (35% versus 12.-5%, P < 0.001).

CONCLUSION

Complicated deliveries, including cases of major bleeding and surgical interventions (CS, MRP), must be recognised as a risk factor, requiring estimation of fetomaternal haemorrhage volume and adjustment of RhIg dosing. The higher miscarriage rate suggests that existing RhIg protocols need adjustment or better compliance.

Estimating the risks of prehospital transfusion of D-positive whole blood to trauma patients who are bleeding in England

Background and Objectives

D‐negative red cells are transfused to D‐negative females of childbearing potential (CBP) to prevent haemolytic disease of the foetus and newborn (HDFN). Transfusion of low‐titre group O whole blood (LTOWB) prehospital is gaining interest, to potentially improve clinical outcomes and for logistical benefits compared to standard of care. Enhanced donor selection requirements and reduced shelf‐life of LTOWB compared to red cells makes the provision of this product challenging.

Materials and Methods

A universal policy change to the use of D‐positive LTOWB across England was modelled in terms of risk of three specific harms occurring: risk of haemolytic transfusion reaction now or in the future, and the risk of HDFN in future pregnancies for all recipients or D‐negative females of CBP.

Results

The risk of any of the three harms occurring for all recipients was 1:14 × 10³ transfusions (credibility interval [CI] 56 × 10²–42 × 10³) while for females of CBP it was 1:520 transfusions (CI 250–1700). The latter was dominated by HDFN risk, which would be expected to occur once every 5.7 years (CI 2.6–22.5). We estimated that a survival benefit of ≥1% using LTOWB would result in more life‐years gained than lost if D‐positive units were transfused exclusively. These risks would be lower, if D‐positive blood were only transfused when D‐negative units are unavailable.

Conclusion

These data suggest that the risk of transfusing RhD‐positive blood is low in the prehospital setting and must be balanced against its potential benefits.

THOR-AABB Working Party Recommendations for a Prehospital Blood Product Transfusion Program

The evidence for the lifesaving benefits of prehospital transfusions is increasing. As such, emergency medical services (EMS) might increasingly become interested in providing this important intervention. While a few EMS and air medical agencies have been providing exclusively red blood cell (RBC) transfusions to their patients for many years, transfusing plasma in addition to the RBCs, or simply using low titer group O whole blood (LTOWB) in place of two separate components, will be a novel experience for many services. The recommendations presented in this document were created by the Trauma, Hemostasis and Oxygenation Research (THOR)-AABB (formerly known as the American Association of Blood Banks) Working Party, and they are intended to provide a framework for implementing prehospital blood transfusion programs in line with the best available evidence. These recommendations cover all aspects of such a program including storing, transporting, and transfusing blood products in the prehospital phase of hemorrhagic resuscitation.

Survey of the RhD selection and issuing practices for uncrossmatched blood products at pediatric trauma hospitals in the United States: The BEST collaborative study

BACKGROUND

As evidence demonstrating the importance of early transfusions in trauma resuscitation accumulates, when RhD-negative products might not be available, it is important to understand the nature of the RhD-type of products provided to bleeding pediatric patients of potentially unknown RhD-type.

METHODS

A survey link was electronically sent to the transfusion service medical director and/or laboratory manager at American pediatric Level I and Level II hospitals inquiring about their practices for selecting RhD-type of uncrossmatched red blood cells (RBC) or low titer group O whole blood (LTOWB) for boys and girls.

RESULTS

There were 55/117 (47.0%) analyzable responses; 43/55 (78.2%) from Level I and 12/55 (21.8%) from Level II hospitals. For in hospital transfusions, 51/55 (92.7%) of centers use only RhD-negative blood products to resuscitate girls ≤18 years old while 30/55 (54.5%) of centers do the same for boys ≤18 years old. Most centers 41/55(74.5%) store RBCs and/or LTOWB in in-hospital remote refrigerators; 27 store only RhD-negative RBCs and 2 store only RhD-negative LTOWB units in these refrigerators. A total of 24/55 (43.6%) centers have RBCs and/or LTOWB available on road ambulances or helicopters for prehospital transfusion; 12 transport only RhD-negative RBCs and two transport only RhD-negative LTOWB. Most centers, 35/55 (63.6%), address the prophylaxis of an RhD-negative female recipient of RhD-positive transfusion on a case-by-case basis.

CONCLUSION

While there is some variability, most of the responding pediatric trauma centers routinely utilized RhD-negative RBCs for emergency transfusion for patients ≤18 years old of unknown RhD-type.

The combined effect of anti-D and non-D Rh antibodies in maternal alloimmunization

Objective

This study aims to investigate the distribution of antibodies that cause hemolytic disease of the fetus and newborn (HDFN) and compare the clinical outcomes of pregnancies affected by anti-D and anti-D combined with non-D Rh alloimmunization.

Materials and Methods

We retrospectively searched and obtained the perinatal and neonatal data of patients with anti-D antibodies and anti-D combined with non-D Rh antibodies (anti-c, -C, -e, -E, and -Kell) from October 2015 to December 2018 at the University of Health Sciences Turkey, Kanuni Sultan Süleyman Training and Research Hospital. Univariate and multiple logistic regression analyses and adjusted odds ratios with their confidence intervals were used to define independent risk factors for non-D antibody positive.

Results

The severe fetal hydrops rate was significantly higher in the anti-D combined non-D group (3/25, 12%) than in the anti-D group (1/128, 0.08%, p<0.001). The intrauterine transfusion (IUT) requirement in the anti-D combined non-D group (16/25, 64%) tended to be significantly higher than that in the anti-D group (5/128, 7.46%, p<0.001). The incidence of neonatal exchange transfusion, top-up transfusion, and postnatal phototherapy frequency in the anti-D combined non-D group was significantly higher than in the anti-D group.

Conclusion

Anti-D combined with another non-D Rh alloantibody resulted in significantly higher HDFN rates than the anti-D alloimmunized pregnancies. Also, anti-D in association with non-D Rh antibodies resulted in more severe HDFN requiring more invasive treatment procedures, including IUT, neonatal exchange transfusion, or top-up transfusion.

Management and clinical consequences of red blood cell antibodies in pregnancy: A population-based cohort study

INTRODUCTION

Anti-D alloimmunization is the most common cause of severe hemolytic disease of the fetus and newborn (HDFN). The management of pregnancies affected by less frequent red blood cell (RBC) antibodies poses a challenge to clinicians, and perinatal outcomes are less well described. This study aimed to describe the frequency of clinically significant RBC antibodies in our pregnant population and analyze the risk of prenatal and postnatal treatment for HDFN in relation to our national risk classification system and management guidelines.

MATERIAL AND METHODS

A retrospective cohort study in the population of all alloimmunized singleton pregnancies in the Stockholm region 1990-2016. Descriptive summaries of different RBC antibodies and pregnancy outcomes were presented, the risks of intrauterine blood transfusion (IUT) and neonatal treatment for HDFN were estimated by type of antibodies.

RESULTS

Of the 1724 alloimmunized pregnancies, 1079 (63%) were at risk of HDFN and constituted our study cohort. Anti-D was detected in 492 (46%) pregnancies, followed by anti-E in 161 (15%), and anti-c in 128 (12%). Eighty-seven (8%) pregnancies had IUT, with the highest risk in pregnancies affected by anti-D combined with other antibodies. The maximum titer recorded before IUT was 64 or above, except for two pregnancies affected by anti-c, for which the maximum titers were 8 and 16. For the 942 (95%) live-born neonates from 992 alloimmunized pregnancies without IUT, the median gestational age at birth was 38⁺⁵  weeks compared with 35⁺⁵  weeks for those who had IUT. Neonatal treatment was most common in the anti-D alone and anti-D combined groups, with 136 (57%) and 21 (44%), respectively, treated with phototherapy and 35 (15%) and 9 (20%) receiving exchange transfusions, respectively. For pregnancies complicated by moderate- and low-risk antibodies, phototherapy was less frequent (32 [36%] and 21 [19%]) and exchange transfusion was rare (5 [6%] and 3 [3%]).

CONCLUSIONS

Anti-D, especially in combination with other antibodies, presents the highest risk of severe HDFN. The classification of less frequent and less well-known RBC antibodies into risk groups can help clinicians in assessing the risk of HDFN and counseling alloimmunized pregnant women regarding the risk of prenatal and postnatal treatments.

Perception of risk in massive transfusion as it relates to fetal outcomes: A survey of surgeons and nurses at one American trauma center

BACKGROUND

The use of blood products early in the resuscitation of bleeding trauma patients is widely accepted, but made difficult by limited supplies of D- red blood cell (RBC)-containing products. Use of D+ RBC-containing products would alleviate this issue, but could lead to alloimmunization. Risk associated with transfusing D+ RBC in emergency bleeding situations is being reconsidered. The level of concern surrounding emergency transfusion as it relates to future fetal harm was surveyed among surgeons and nurses.

METHODS

Faculty and staff in the Departments of Surgery and Nursing were surveyed on the risks of receiving an emergency RBC transfusion and the subsequent potential for fetal harm. Answers were grouped as likely to accept (likely/very likely) or refuse transfusion (unlikely/very unlikely). Participants were compared by sex, and women by child-bearing age, ([15-50 years] vs. [>50 years]).

RESULTS

Ninety surveys were initiated with 76 fully completed. Male (n = 39) and female (n = 37) respondents were comparable. Most female respondents (30/37, 81%) were of childbearing age. Overall, both males (38/39, 95%) and females (33/37, 89%; p = .19) were likely to accept a transfusion in an emergency. There was no difference in transfusion acceptance if the risk of fetal harm was presented as 1% (p = .73) or 0.1% (p = .51). Most females (34/37, 92%) were not opposed to transfusion even if there was an unspecified risk of future fetal harm.

CONCLUSION

Most of the surgeons and nurses who responded would accept a transfusion in an emergency situation even if it might lead to harming a future fetus.

Rate of RhD-alloimmunization after the transfusion of RhD-positive red blood cell containing products among injured patients of childbearing age: single center experience and narrative literature review

OBJECTIVES

To determine the rate of RhD-alloimmunization in injured RhD-negative patients in the age range of childbearing potential who were transfused with at least one unit of RhD-positive red blood cells (RBC) or low titer group O whole blood (LTOWB).

METHODS

Injured RhD-negative patients between the ages of 13-50 at an American Level 1 trauma center who were transfused with at least one unit of RBCs or LTOWB during their resuscitation and who had an antibody detection test performed at least 14 days afterwards were included.

RESULTS

Over a 20-year period, 96 study-eligible patients were identified, of which 90/96 (93.8%) were male. The median age of these 96 patients was 33 (5th-95th percentiles: 19-49) years. The majority of these patients (71/96, 74.0%) had an injury severity score (ISS) greater than 15. Overall, 41/96 (42.7%; 95% CI: 32.7%-53.2%) of these patients became alloimmunized after receipt of a median of 3 (5th-95th percentiles: 1-35) units of RhD-positive RBCs and/or LTOWB. There was no association between receipt of leukoreduced RBCs or receipt of LTOWB and the RhD-alloimmunization rate.

DISCUSSION

The rate of RhD-alloimmunization in this study was at the higher end of rates that have been reported. None of the previous studies focused exclusively on trauma patients in the childbearing age range.

CONCLUSION

The 42.7% rate of RhD-alloimmunization in a predominantly male trauma population could probably be extrapolated to women in the same age range when estimating their risk of RhD-alloimmunization following RhD-positive transfusion.

Survey of group A plasma and low-titer group O whole blood use in trauma resuscitation at adult civilian level 1 trauma centers in the US

BACKGROUND

Recently revisited products like low-titer group O whole blood (LTOWB) and novel applications of group A as a universal donor of plasma are being used for trauma resuscitation. A survey of American Level 1 trauma centers was performed to elucidate the extent to which these products are currently employed.

METHODS

A survey was written that probed into the current use of blood products in trauma resuscitation with specific emphasis on LTOWB and group A plasma. A list of adult civilian Level 1 trauma centers in the continental USA was obtained from two public surgery and trauma focused websites. An email was then sent to each center's transfusion service medical director or laboratory manager providing them with a link to the online survey.

RESULTS

Responses were received from 103/187 (55%) adult civilian Level 1 trauma centers. For the resuscitation of trauma patients, group A plasma was used at 94/103 (91%) centers, while LTOWB was used at 43/103 (42%) centers. There were 39/103 (38%) centers that used both products. At 62/94 (66%) of the centers that used group A plasma, there was no limit on the number of units that could be administered, while an unlimited number of LTOWB units could be used at 5/43 (12%) of the centers that used LTOWB. RhD-positive LTOWB could be transfused to RhD-negative or RhD-type unknown females of childbearing potential at 22/43 (51%) of centers.

CONCLUSION

The use of group A plasma and LTOWB in trauma is increasing at American Level 1 trauma centers.

Reduction of anti-K-mediated hemolytic disease of newborns after the introduction of a matched transfusion policy: A nation-wide policy change evaluation study in the Netherlands

BACKGROUND

During pregnancy, maternal red blood cell (RBC) antibodies can lead to life-threatening fetal hemolysis and anemia. Women can become immunized by a pregnancy or an unmatched transfusion. Our aim was to quantify the effect of a nationwide K-matched transfusion policy for women of childbearing age potential to prevent K-immunization in pregnancy.

STUDY DESIGN AND METHODS

In this nation-wide policy change evaluation study we determined the occurrence of RBC antibodies before and after introduction of a K-matched transfusion policy and evaluated the cause K alloimmunization 10 years after introduction of this measure. K-matched transfusion for females under 45 years of age is advised in the Dutch transfusion guideline since 2004. We used laboratory data from pregnancies with RBC antibodies identified in the period 1999-2018 obtained as part of a population-based screening program in the Netherlands.

RESULTS

Tests of 36 286 pregnancies produced a positive antibody screening result which concerned anti-K in 1550 pregnancies. The occurrence of anti-K decreased from 67.9 to 20.2 per 100 000 pregnancies. The relative risk reduction was 0.70 which largely exceeded the relative risk reduction of 0.27 for antibodies against RBC antigens for which no preventive matching is required. The number of pregnancies at risk for anti-K-mediated disease decreased from 9.7 to 4.2 per 100 000 pregnancies.

CONCLUSIONS

A K-matched transfusion policy is associated with a major decrease in a number of pregnant women with anti-K and pregnancies at risk for anti-K-mediated disease. A relatively simple measure is now shown to impact prevention of hemolytic disease in the fetus and newborn.

The risk to future pregnancies of transfusing Rh(D)-negative females of childbearing potential with Rh(D)-positive red blood cells during trauma resuscitation is dependent on their age at transfusion

BACKGROUND

A risk assessment model for predicting the risk of haemolytic disease of the fetus and newborn (HDFN) in future pregnancies following the transfusion of Rh(D)-positive red blood cell (RBC)-containing products to females of childbearing potential (FCP) was developed, accounting for the age that the FCP is transfused in various countries.

METHODS

The HDFN risk prediction model included the following inputs: risk of FCP death in trauma, Rh(D) alloimmunization rate following Rh(D)-positive RBC transfusion, expected number of live births following resuscitation, probability of carrying an Rh(D)-positive fetus, the probability of HDFN in an Rh(D)-positive fetus carried by an alloimmunized mother. The model was implemented in Microsoft R Open, and one million FCPs of each age between 18 and 49 years old were simulated. Published data from eight countries, including the United States, were utilized to generate country-specific HDFN risk estimates.

RESULTS

The risk predictions showed similar characteristics for each country in that the overall risk of having a pregnancy affected by HDFN was higher if the FCP was younger when she received her Rh(D)-positive transfusion than if she was older. In the United States, the overall risk of HDFN if the FCP was transfused at age 18 was 3·4% (mild: 1·20%, moderate: 0·45%; severe: 1·15%; IUFD: 0·57%); the risk was approximately 0% if the FCP was 43 years or older at the time of transfusion.

CONCLUSION

This model can be used to predict HDFN outcomes when establishing transfusion policies as it relates to the administration of Rh(D)-positive products for massively bleeding FCPs.

Non-immune hydrops fetalis was rare in Sweden during 1997-2015, but cases were associated with complications and poor prognosis

AIM

The study was designed to document the incidence of non-immune hydrops fetalis (NIHF) at birth and characterise associated outcomes and obstetric complications.

METHODS

Data on more than 1.9 million births were extracted from the Swedish Birth Register for 1997-2015. Pregnancies not affected by NIHF served as controls. National registers on mortality and hospitalisations provided follow-up information.

RESULTS

There were 309 cases of NIHF at birth corresponding to an incidence of 1.6 per 10 000, lower than in previous studies. NIHF was more frequent in mothers aged ≥35 years and with a history of stillbirth. Preterm delivery occurred in 77.7% in the NIHF group, including 31.7% before 32 weeks of gestation. Multiple births and Caesarean sections were reported more frequent in the NIHF group. NIHF was associated with poor outcome with 14.6% stillbirths and in 26.5% early neonatal death. Overall, 58.7% of live-born children with NIHF were alive at 12 months compared with 99.7% of controls. The most common causes of death were cardiovascular diseases and thoracic abnormalities.

CONCLUSION

NIHF at birth is associated with obstetric complications and poor prognosis for the neonate related to underlying disease. The low incidence of NIHF observed in this study may reflect well-developed antenatal care.

RhIg for the prevention Rh immunization and IVIg for the treatment of affected neonates

Rhesus D (RhD) negative pregnant women carrying an RhD positive fetus are at risk of developing anti-D during or after pregnancy. Anti-d-immunoglobulin (RhIg), which is mainly produced from special plasma donated in a few countries for the whole world, is able to prevent an anti-D alloimmunization. Through the introduction of ante- and postnatal anti-d-prophylaxis into clinical routine, the frequency of hemolytic disease of fetus and newborn decreased considerably. Postnatal prophylaxis from the beginning in the 1960s has been applied only to women who delivered an RhD positive newborn. Because the fetal RhD status can be determined with high sensitivity and accuracy from the mother's peripheral blood, targeted antenatal anti-d-prophylaxis is becoming a new standard procedure in more and more countries. Phototherapy and exchange transfusion are still the main pillars for the treatment of RhD hemolytic disease of the newborn. The efficacy of IVIg in the management of these neonates is not conclusive and cannot be recommended until a larger randomized, double-blind, placebo-controlled study is performed.

Non-invasive prenatal testing for management of haemolytic disease of the fetus and newborn induced by maternal alloimmunisation

Anti-D immunoglobulin prophylaxis reduces the risk of RhD negative women becoming alloimmunised to the RhD antigen and is a major preventative strategy in reducing the burden of haemolytic disease of the fetus and newborn (HDFN). HDFN also arises from other maternal red cell antibodies, with the most clinically significant, after anti-D, being anti-K, anti-c and anti-E. Among the 39 human blood group systems advanced genomic technologies are still revealing novel or rare antigens involved in maternal alloimmunisation. Where clinically significant maternal antibodies are detected in pregnancy, non-invasive prenatal testing (NIPT) of cell-free fetal DNA provides a safe way to assess the fetal blood group antigen status. This provides information as to the risk for HDFN and thus guides management strategies. In many countries, NIPT fetal RHD genotyping as a diagnostic test using real-time PCR has already been integrated into routine clinical care for the management of women with allo-anti-D to assess the risk for HDFN. In addition, screening programs have been established to provide antenatal assessment of the fetal RHD genotype in non-alloimmunised RhD negative pregnant women to target anti-D prophylaxis to those predicted to be carrying an RhD positive baby. Both diagnostic and screening assays exhibit high accuracy (over 99 %). NIPT fetal genotyping for atypical (other than RhD) blood group antigens presents more challenges as most arise from a single nucleotide variant. Recent studies show potential for genomic and digital technologies to provide a personalised medicine approach with NIPT to assess fetal blood group status for women with other (non-D) red cell antibodies to manage the risk for HDFN.

Three non-classical mechanisms for anemic disease of the fetus and newborn, based on maternal anti-Kell, anti-Ge3, anti-M, and anti-Jra cases

Maternal alloantibody-mediated hemolytic disease of the fetus and newborn (HDFN) ranges from no or mild symptoms to severe hydrops and intrauterine fetal demise. Hemolytic anti-D-mediated HDFN proceeds via a long-known mechanism, to which three other pathways to fetal/neonatal anemia may be added: (0) Fetal erythrocyte destruction can proceed by extravascular phagocytosis. (1) An apoptotic pathway has been described for anti-Kell, and anti-Ge3. (2) Erythropoietic suppression may arise from altered or deformed erythroblast architecture in anti-M-mediated disease. (3) Clonal escape from erythropoietic suppression is hypothesized to arise from maternal anti-Jr^a immune pressure, albeit this requires further elucidation. Alloantibody-mediated anemic disease of the fetus and newborn (ADFN) is a designation we favor for cases when hemolysis or hyperbilirubinemia are not the dominant features, such as those provoked by anti-Kell, anti-Ge3, anti-M, and anti-Jr^a.

The rhesus incompatible pregnancy and its consequences for affected fetuses and neonates

Rhesus incompatibility in pregnancy may result in haemolytic disease of the fetus and newborn (HDFN). This review discusses the fetal, neonatal and long-term consequences of HDFN and its management. Untreated, the fetal and neonatal prognosis of HDFN is poor. Provision of intravascular intrauterine transfusion (IUT) in a dedicated referral centre significantly reduces perinatal loss. Early-onset, severe fetal anaemia carries a greater risk of adverse fetal and neonatal outcomes and is less amenable to treatment with IUT. Interventions to prevent and treat severe, early onset disease have been investigated, however evidence from randomised controlled trials is required. Neonatal consequences of Rhesus haemolytic disease include early and late postnatal anaemia, and hyperbilirubinaemia leading to bilirubin-induced neurological dysfunction. Neurodevelopmental impairment and adult cardiovascular disease are long-term complications that have been reported in association with severe fetal anaemia. Strategies to prevent fetal hydrops, and further research into the long-term impacts of fetal anaemia may improve health outcomes for adult survivors of HDFN.

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

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.

Medical therapy to attenuate fetal anaemia in severe maternal red cell alloimmunisation

Haemolytic disease of the fetus and newborn (HDFN) remains an important cause of fetal mortality with potential neonatal and longer-term morbidity. HDFN is caused by maternal red cell alloimmunisation, with IgG antibodies crossing the placenta to destroy fetal erythroid cells expressing the involved antigen. Intrauterine fetal blood transfusion is the therapy of choice for severe fetal anaemia. Despite a strong evidence base and technical advances, invasive fetal therapy carries risk of miscarriage and preterm birth. Procedure-related risks are increased when invasive, in utero transfusion is instituted prior to 22 weeks to treat severe early-onset fetal anaemia. This review focuses upon this cohort of HDFN and discusses intravenous immunoglobin (IVIg) and novel monoclonal antibody (M281, nipocalimab) treatments which, if started at the end of the first trimester, may attenuate the transplacental passage and fetal effects of IgG antibodies. Such therapy has the ability to improve fetal survival in this severe presentation of HDFN when early in utero transfusion may be required and may have wider implications for the perinatal management in general.

Red cell alloimmunization: A 2020 update

Management of maternal red cell alloimmunization has been revolutionized over the last 60 years. Advances in the prevention, screening, diagnosis, and treatment of alloimmune-induced fetal anemia make this condition an exemplar for contemporary practice in fetal therapy. Since survival is now an expectation, attention has turned to optimization of long-term outcomes following an alloimmunized pregnancy. In this review, the current management of red cell alloimmunization is described. Current research and future directions are discussed with particular emphasis on later life outcomes after alloimmune fetal anemia.