Anti-D administration in pregnancy for preventing Rhesus alloimmunisation

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.

Complement C3 and marginal zone B cells promote IgG-mediated enhancement of RBC alloimmunization in mice

Administration of anti-RhD immunoglobulin (Ig) to decrease maternal alloimmunization (antibody-mediated immune suppression [AMIS]) was a landmark clinical development. However, IgG has potent immune-stimulatory effects in other settings (antibody-mediated immune enhancement [AMIE]). The dominant thinking has been that IgG causes AMIS for antigens on RBCs but AMIE for soluble antigens. However, we have recently reported that IgG against RBC antigens can cause either AMIS or AMIE as a function of an IgG subclass. Recent advances in mechanistic understanding have demonstrated that RBC alloimmunization requires the IFN-α/-β receptor (IFNAR) and is inhibited by the complement C3 protein. Here, we demonstrate the opposite for AMIE of an RBC alloantigen (IFNAR is not required and C3 enhances). RBC clearance, C3 deposition, and antigen modulation all preceded AMIE, and both CD4+ T cells and marginal zone B cells were required. We detected no significant increase in antigen-specific germinal center B cells, consistent with other studies of RBC alloimmunization that show extrafollicular-like responses. To the best of our knowledge, these findings provide the first evidence of an RBC alloimmunization pathway which is IFNAR independent and C3 dependent, thus further advancing our understanding of RBCs as an immunogen and AMIE as a phenomenon.

Practices for RhD alloimmunization prevention: a vignette-based survey of midwives

INTRODUCTION

Despite the availability guidelines to prevent RhD alloimmunization, severe hemolytic disease of fetus and newborn still occurs in high-income countries. The aim of the study was (1) To assess variations in practices for the prevention of RhD alloimmunization, and (2) to understand midwives' acceptance and appropriation of fetal RhD genotyping.

METHODS

Descriptive cross-sectional survey of French midwives from September 2017 through January 2018. Participants were asked to complete an internet-based questionnaire that included three clinical vignettes. They were questioned about their practices concerning early pregnancy visit by RhD-negative women, prevention of RhD alloimmunization in women with second-trimester metrorrhagia, and RhD fetal genotyping.

RESULTS

A total of 827 midwives completed the questionnaire. Only 21.1% reported that they practice all the preventive measures recommended in early pregnancy. In a situation at high risk of RhD alloimmunization during pregnancy, 97.2% of midwives would perform immunoprophylaxis. Nearly, all midwives reported providing information about RhD alloimmunization (92.4%) at the beginning of pregnancy, although only 11.3% offered both written and verbal information; at the time of systematic anti-D immunoprophylaxis (28 weeks), 78% provided information, but only 2.7% both verbally and in writing. Finally, only 50.8% of midwives preferred to include RhD fetal genotyping in routine prenatal prophylaxis.

DISCUSSION

This study showed significant variations in French midwives' practices to prevent RhD alloimmunization. Better dissemination of guidelines is needed to improve both consistent use of these practices and the quality of information delivered to RhD-negative pregnant women.

Therapeutic plasma exchange in pregnancy: A literature review

Therapeutic plasma exchange (TPE) is indicated as a treatment for a wide array of diseases, extensively addressed in the Guidelines of the American Society for Apheresis. In pregnancy, TPE is an uncommon event and application is largely based on extrapolation of efficacy and safety in a non-pregnant population. This review intends to describe the currently available experience of TPE in pregnancy to help clinicians recognise indications during pregnancy and to support current guideline recommendations with literature-based experiences. In order to identify the clinical indications for which TPE is applied in pregnant women, we performed a literature search including studies till November 2019, without a start date restriction. Data extraction included medical indication for TPE and safety of TPE in pregnant women. 279 studies were included for analysis. Nowadays, TPE is predominantly applied for thrombotic microangiopathies, lipid disorders and a variety of autoimmune diseases. The application of TPE during pregnancy remains largely empiric and relies on individual case reports in the absence of high-quality studies and definitive evidence-based guidelines. Safety profile of TPE during pregnancy appears to be comparable to application of TPE in non-pregnant patients. In conclusion, based on the limited evidence that we found in literature with a high risk of publication bias, TPE procedures can be used safely during pregnancy with the appropriate preparation and experience of a multidisciplinary team.

FIGO/ICM guidelines for preventing Rhesus disease: A call to action

The introduction of anti‐Rh(D) immunoglobulin more than 50 years ago has resulted in only a 50% decrease in Rhesus disease globally owing to a low uptake of this prophylactic approach. The International Federation of Gynecology and Obstetrics, International Confederation of Midwives, and Worldwide Initiative for Rhesus Disease Eradication have reviewed current evidence regarding the utility of anti‐Rh(D) immunoglobulin. Taking into account the effectiveness anti‐Rh(D), the new guidelines propose adjusting the dose for different indications and prioritizing its administration by indication.

These FIGO/ICM guidelines review the evidence regarding the usefulness of anti‐Rh(D) immunoglobulin, prioritizing its administration by indication.

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.

Single-stranded DNA aptamer targeting and neutralization of anti-D alloantibody: a potential therapeutic strategy for haemolytic diseases caused by Rhesus alloantibody

BACKGROUND

Rhesus (Rh) D antigen is the most important antigen in the Rh blood group system because of its strong immunogenicity. When RhD-negative individuals are exposed to RhD-positive blood, they may produce anti-D alloantibody, potentially resulting in delayed haemolytic transfusion reactions and Rh haemolytic disease of the foetus and newborn, which are difficult to treat. Inhibition of the binding of anti-D antibody with RhD antigens on the surface of red blood cells may effectively prevent immune haemolytic diseases.

MATERIALS AND METHODS

In this study, single-stranded (ss) DNA aptamers, specifically binding to anti-D antibodies, were selected via systematic evolution of ligands by exponential enrichment (SELEX) technology. After 14 rounds of selection, the purified ssDNA was sequenced using a Personal Genome Machine system. Haemagglutination inhibition assays were performed to screen aptamers for biological activity in terms of blocking antigen-antibody reactions: the affinity and specificity of the aptamers were also determined.

RESULTS

In addition to high specificity, the aptamers which were selected showed high affinity for anti-D antibodies with dissociation constant (K_d) values ranging from 51.46±14.90 to 543.30±92.59 nM. By the combined use of specific ssDNA aptamer 7 and auxiliary ssDNA aptamer 2, anti-D could be effectively neutralised at low concentrations of the aptamers.

DISCUSSION

Our results demonstrate that ssDNA aptamers may be a novel, promising strategy for the treatment of delayed haemolytic transfusion reactions and Rh haemolytic disease of the foetus and newborn.

Rare problems with RhD immunoglobulin for postnatal prophylaxis after large fetomaternal haemorrhage

We report a case of unusually large fetomaternal haemorrhage in a RhD- patient; of symptomatic non-sustained haemolysis of fetal red cells in the maternal circulation with infusion of intravenous high-dose RhD immunoglobulin; and of a failure to prevent RhD alloimmunisation. The haemolytic reaction is not previously reported in this patient group and we suggest would be limited to patients where the number of fetal red cells in the circulation is high. We advocate caution in treatment and spaced dosing of RhD immunoglobulin where the required dose is high, and refer readers to the WinRhoSDF™ RhD immunoglobulin product information for their updated dosing recommendations. There is a need for better understanding of pathophysiology and RhD immunoglobulin effects, to further reduce alloimmunisation rates, and we support the reporting of prophylaxis failures to haemovigilance programmes as is in place in the United Kingdom.

Risk factors for acute bilirubin encephalopathy on admission to two Myanmar national paediatric hospitals

Background

Jaundice is the commonest neonatal ailment requiring treatment. Untreated, it can lead to acute bilirubin encephalopathy (ABE), chronic bilirubin encephalopathy (CBE) or death. ABE and CBE have been largely eliminated in industrialised countries, but remain a problem of largely undocumented scale in low resource settings.

As part of a quality-improvement intervention in the Neonatal Care Units of two paediatric referral hospitals in Myanmar, hospitals collected de-identified data on each neonate treated on new phototherapy machines over 13–20 months. The information collected included: diagnosis of ABE at hospital presentation; general characteristics such as place of birth, source of referral, and sex; and a selection of suspected causes of jaundice including prematurity, infection, G6PD status, ABO and Rh incompatibility. This information was analysed to identify risk factors for hospital presentation with ABE, using multiple logistic regression.

Results

Data on 251 neonates was recorded over 20 months in Hospital A, and 339 neonates over 13 months in Hospital B; the number of outborn neonates presenting with ABE was 32 (12.7 %) and 72 (21.2 %) respectively. In the merged dataset the final multivariate model identified the following independent risk and protective factors: home birth, OR_adj = 2.3 (95 % CI: 1.04-5.4); self-referral, OR_adj = 2.6 (95 % CI: 1.2-6.0); prematurity, OR_adj = 0.40 (95 % CI: 0.18-0.85); and a significant interaction between hospital and screening status because screening positive for G6PD deficiency was a strong and significant risk factor at Hospital B (OR_adj = 5.9; 95 % CI: 3.0-11.6), but not Hospital A (OR_adj = 1.1; 95 % CI: 0.5-2.5).

Conclusion

The study identifies home birth, self-referral and G6PD screening status as important risk factors for presentation with ABE; prematurity was protective, but this is interpreted as an artefact of the study design. As operational research, there is likely to be substantial measurement error in the risk factor data, suggesting that the identified risk factor estimates are robust. Additional interventions are required to ensure prompt referral of jaundiced neonates to treatment facilities, with particular focus on home births and communities with high rates of G6PD deficiency.

Anti-D administration in pregnancy for preventing Rhesus alloimmunisation

BACKGROUND

During pregnancy, a Rhesus negative (Rh-negative) woman may develop antibodies when her fetus is Rhesus positive (Rh-positive). These antibodies may harm Rh-positive babies.

OBJECTIVES

To assess the effects of antenatal anti-D immunoglobulin on the incidence of Rhesus D alloimmunisation when given to Rh-negative women without anti-D antibodies.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials in Rh-negative women without anti-D antibodies given anti-D after 28 weeks of pregnancy, compared with no treatment, placebo or a different regimen of anti-D.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

We included two trials involving over 4500 women, comparing anti-D prophylaxis with no anti-D during pregnancy in this review. Overall, the trials were judged to be at moderate to high risk of bias. The quality of the evidence for pre-specified outcomes was also assessed using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach.In regards to primary review outcomes, there did not appear to be a clear difference in the risks of immunisation when women who received anti-D at 28 and 34 weeks' gestation were compared with women who were not given antenatal anti-D: risk ratio (RR) for incidence of Rhesus D alloimmunisation during pregnancy was 0.42 (95% confidence interval (CI) 0.15 to 1.17, two trials, 3902 women; GRADE: low quality evidence); at birth of a Rh-positive infant the RR was 0.42 (95% CI 0.15 to 1.17, two trials, 2297 women); and within 12 months after birth of a Rh-positive infant the average RR was 0.39 (95% CI 0.10 to 1.62, two trials, 2048 women; Tau²: 0.47; I²: 39%; GRADE: low quality evidence). Neither of the trials reported on incidence of Rhesus D alloimmunisation in subsequent pregnancies.Considering secondary outcomes, in one trial, women receiving anti-D during pregnancy were shown to be less likely to register a positive Kleihauer test (which detects fetal cells in maternal blood) in pregnancy (at 32 to 25 weeks) (RR 0.60, 95% CI 0.41 to 0.88; 1884 women; GRADE: low quality evidence) and at the birth of a Rh-positive infant (RR 0.60, 95% CI 0.46 to 0.79; 1189 women; GRADE: low quality evidence). No clear differences were seen for neonatal jaundice (RR 0.26, 95% CI 0.03 to 2.30; 1882 infants; GRADE: very low quality evidence). Neither of the trials reported on adverse effects associated with anti-D treatment.

AUTHORS' CONCLUSIONS

Existing studies do not provide conclusive evidence that the use of anti-D during pregnancy benefits either mother or baby in terms of incidence of Rhesus D alloimmunisation during the pregnancy or postpartum, or the incidence of neonatal morbidity (jaundice) (low to very low quality evidence). However women receiving anti-D may be less likely to register a positive Kleihauer test in pregnancy and at the birth of a Rh-positive infant (low quality evidence). Fewer women who receive anti-D during pregnancy may have Rhesus D antibodies in a subsequent pregnancy, with benefits for the baby, however this needs to be tested in studies of robust design.

Financial implications of RHD genotyping of pregnant women with a serologic weak D phenotype

BACKGROUND

Hemolytic disease of the fetus and newborn, classically caused by maternal-fetal incompatibility of the Rh blood group D antigen, can be prevented by RhIG prophylaxis. While prophylactic practices for pregnant women with serologic weak D phenotypes vary widely, RHD genotyping could provide clear guidance for management. This analysis evaluated the financial implications of using RHD genotyping to guide RhIG prophylaxis among pregnant females.

STUDY DESIGN AND METHODS

A Markov-based model was constructed to evaluate the costs of RHD genotyping for pregnant females with serologic weak D phenotypes to inform RhIG prophylaxis. Using a comparison strategy of managing these women conservatively as D-, direct medical costs were assessed over 10- and 20-year periods for a simulated population of US women. One-way and probabilistic sensitivity analyses were used to assess the robustness of conclusions.

RESULTS

Using base-case variables, RHD genotyping for pregnant women with serologic weak D phenotypes is expected to marginally reduce overall costs. RHD genotyping these patients, rather than conservatively managing them as D-, would be cost-saving when the cost of genotyping is below $256. Genotyping would decrease net costs among non-Hispanic Caucasian females (-$0.17/pregnancy), but would increase costs among non-Hispanic African Americans (+$0.51/pregnancy), non-Hispanic American Indian/Alaskans (+$0.10/pregnancy), and Hispanics (+$0.37/pregnancy). Incorporating RHD genotyping would not significantly impact costs among Asians and Hawaiians/Pacific Islanders.

CONCLUSIONS

Using RHD genotyping to guide RhIG prophylaxis among pregnant women with serologic weak D phenotypes may be clinically beneficial without increasing overall costs.

Appropriate provision of anti-D prophylaxis to RhD negative pregnant women: a scoping review

BACKGROUND

The purpose of this scoping review was to review the literature on healthcare provider provision of anti-D prophylaxis to RhD negative pregnant women in appropriate clinical situations in various healthcare settings.

METHODS

A scoping review framework was used to structure the process. The following databases were searched: CINAHL (EBSCO), EBM Reviews (OvidSP), Embase (OvidSP), Medline (OvidSP), and Web of Science (ISI). In addition, hand searching of article references was conducted. The search yielded 301 articles. Thirty-five articles remained for review after screening. Two team members reviewed each article using a detailed data collection sheet. A third reviewer was utilized if discrepancies occurred amongst reviewers.

RESULTS

The review process yielded 18 included articles. The majority of the studies were conducted in the United Kingdom. Of the 18 studies, 15 were retrospective studies. The articles were largely conducted in one institution. The articles with a focus on routine antenatal provision of anti-D immunoglobulin found that it was given 80 to 90% of the time. Postpartum provision of anti-D immunoglobulin had significantly higher results of 95-100%. The review found that the delivery of anti-D immunoglobulin to RhD negative pregnant women during situations of potential sensitizing events was suboptimal.

CONCLUSIONS

The included articles examine the management of RhD negative pregnancies in various countries with existing national guidelines. The existing evidence indicates an opportunity for quality improvement in situations where potential sensitizing events are not at routine times in pregnancy, such as miscarriage or fetal demise early in pregnancy. Routine care for the prevention of RhD alloimmunization in pregnancy and postpartum appears to be fairly consistent. The paucity of recent literature in this area leads to a recommendation for further research.

Midwifery and quality care: findings from a new evidence-informed framework for maternal and newborn care

In this first paper in a series of four papers on midwifery, we aimed to examine, comprehensively and systematically, the contribution midwifery can make to the quality of care of women and infants globally, and the role of midwives and others in providing midwifery care. Drawing on international definitions and current practice, we mapped the scope of midwifery. We then developed a framework for quality maternal and newborn care using a mixed-methods approach including synthesis of findings from systematic reviews of women's views and experiences, effective practices, and maternal and newborn care providers. The framework differentiates between what care is provided and how and by whom it is provided, and describes the care and services that childbearing women and newborn infants need in all settings. We identified more than 50 short-term, medium-term, and long-term outcomes that could be improved by care within the scope of midwifery; reduced maternal and neonatal mortality and morbidity, reduced stillbirth and preterm birth, decreased number of unnecessary interventions, and improved psychosocial and public health outcomes. Midwifery was associated with more efficient use of resources and improved outcomes when provided by midwives who were educated, trained, licensed, and regulated. Our findings support a system-level shift from maternal and newborn care focused on identification and treatment of pathology for the minority to skilled care for all. This change includes preventive and supportive care that works to strengthen women's capabilities in the context of respectful relationships, is tailored to their needs, focuses on promotion of normal reproductive processes, and in which first-line management of complications and accessible emergency treatment are provided when needed. Midwifery is pivotal to this approach, which requires effective interdisciplinary teamwork and integration across facility and community settings. Future planning for maternal and newborn care systems can benefit from using the quality framework in planning workforce development and resource allocation.

Can available interventions end preventable deaths in mothers, newborn babies, and stillbirths, and at what cost?

Progress in newborn survival has been slow, and even more so for reductions in stillbirths. To meet Every Newborn targets of ten or fewer neonatal deaths and ten or fewer stillbirths per 1000 births in every country by 2035 will necessitate accelerated scale-up of the most effective care targeting major causes of newborn deaths. We have systematically reviewed interventions across the continuum of care and various delivery platforms, and then modelled the effect and cost of scale-up in the 75 high-burden Countdown countries. Closure of the quality gap through the provision of effective care for all women and newborn babies delivering in facilities could prevent an estimated 113,000 maternal deaths, 531,000 stillbirths, and 1·325 million neonatal deaths annually by 2020 at an estimated running cost of US$4·5 billion per year (US$0·9 per person). Increased coverage and quality of preconception, antenatal, intrapartum, and postnatal interventions by 2025 could avert 71% of neonatal deaths (1·9 million [range 1·6-2·1 million]), 33% of stillbirths (0·82 million [0·60-0·93 million]), and 54% of maternal deaths (0·16 million [0·14-0·17 million]) per year. These reductions can be achieved at an annual incremental running cost of US$5·65 billion (US$1·15 per person), which amounts to US$1928 for each life saved, including stillbirths, neonatal, and maternal deaths. Most (82%) of this effect is attributable to facility-based care which, although more expensive than community-based strategies, improves the likelihood of survival. Most of the running costs are also for facility-based care (US$3·66 billion or 64%), even without the cost of new hospitals and country-specific capital inputs being factored in. The maximum effect on neonatal deaths is through interventions delivered during labour and birth, including for obstetric complications (41%), followed by care of small and ill newborn babies (30%). To meet the unmet need for family planning with modern contraceptives would be synergistic, and would contribute to around a halving of births and therefore deaths. Our analysis also indicates that available interventions can reduce the three most common cause of neonatal mortality--preterm, intrapartum, and infection-related deaths--by 58%, 79%, and 84%, respectively.

Anti-D administration after childbirth for preventing Rhesus alloimmunisation

BACKGROUND

The development of Rh immunisation and its prophylactic use since the 1970s has meant that severe Rhesus D (RhD) alloimmunisation is now rarely seen.

OBJECTIVES

The objective of this systematic review was to assess the effects of giving anti-D to Rhesus negative women, with no anti-D antibodies, who had given birth to a Rhesus positive infant.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register, MEDLINE (from 1966 to January 1999) and reference lists of relevant articles. Date of last search of Cochrane Controlled Trials Register: January 1999.

SELECTION CRITERIA

Randomised trials in Rhesus negative women without antibodies who were given anti-D immunoglobulin postpartum compared with no treatment or placebo.

DATA COLLECTION AND ANALYSIS

Assessments of inclusion criteria, trial quality and data extraction were done by each author independently. Initial analyses included all trials. Other analyses assessed the effect of trial quality, ABO compatibility and dose.

MAIN RESULTS

Six eligible trials compared postpartum anti-D prophylaxis with no treatment or placebo. The trials involved over 10,000 women, but trial quality varied. Anti-D lowered the incidence of RhD alloimmunisation six months after birth (relative risk 0.04, 95% confidence interval 0.02 to 0.06), and in a subsequent pregnancy (relative risk 0.12, 95% confidence interval 0. 07 to 0.23). These benefits were seen regardless of the ABO status of the mother and baby and when anti-D was given within 72 hours of birth. Higher doses (up to 200 micro grams) were more effective than lower doses (up to 50 micro grams) in preventing RhD alloimmunisation in a subsequent pregnancy.

REVIEWER'S CONCLUSIONS

Anti-D, given within 72 hours after childbirth, reduces the risk of RhD alloimmunisation in Rhesus negative women who have given birth to a Rhesus positive infant. However the evidence on the optimal dose is limited.