Following targeted routine antenatal anti-D prophylaxis, almost half of the pregnant women had undetectable anti-D prophylaxis at delivery

Why do people still make anti-D over 50 years after the introduction of Rho(D) immune globulin? A Biomedical Excellence for Safer Transfusion (BEST) Collaborative study

BACKGROUND

Rho(D) immune globulin (RhIg) is used to reduce RhD alloimmunization in pregnancy. This study describes potential causes for RhD alloimmunization after the development and implementation of RhIg.

STUDY DESIGN AND METHODS

This retrospective descriptive study investigated RhD-negative patients born in 1965-2005 with anti-D newly identified during 2018-2022. Transfusion, pregnancy, intravenous drug abuse, and transplantation were considered potential alloimmunization sources.

RESULTS

There were 1200 study patients (852 females; 348 males) at 30 institutions in 5 countries (USA, Canada, UK, New Zealand, Brazil). Most patients had a single potential source of alloimmunization identified (857/1200, 71%), most commonly pregnancy among females (537/852, 63%) and transfusion among males (180/348, 52%). When multiple potential sources were included, males were more likely than females to have a history of transfusion (235/348 [68%] vs. 149/852 [17%], p < .0001) and confirmed or suspected intravenous drug abuse (100/348 [29%] vs. 138/852 [16%], p < .0001). Among females with a history of pregnancy, 119/718 (17%) had healthcare access issues, 120/718 (17%) had pregnancy in a country where they may not have received RhIg, and 21/718 (3%) refused RhIg. Among patients with a history of transfusion, males were more likely than females to have received RhD-positive red blood cells or whole blood (143/235 [61%] vs. 30/149 [20%], p < .0001) and/or platelets (84/235 [36%] vs. 19/149 [13%], p < .0001).

DISCUSSION

Pregnancy was the most frequently identified potential source of RhD alloimmunization among females. Transfusion was most frequent in males. Intravenous drug abuse as a common potential source among patients with RhD alloimmunization merits further study.

Implementation and mixed method evaluation of a unique midwife-prescribed, pharmacist-administered routine antenatal Anti-D prophylaxis model in pregnant people

BACKGROUND

Routine antenatal anti-D prophylaxis, an injected blood product, reduces the risk of rhesus (D) sensitisation in rhesus negative pregnancies. One New Zealand district implemented this service through a unique model using midwives to prescribe and community pharmacists to administer and manage anti-D.

AIM

To describe the model and its implementation and ascertain uptake, cost, acceptability to service users and stakeholders, and potential improvements.

METHODS

An audit compared uptake from October 1, 2021 to May 31, 2023 with the eligible population. A cross-sectional survey of service users, midwives, pharmacists and staff supporting the service delivery was conducted in 2023. A cost analysis was undertaken.

RESULTS

At least one dose of anti-D was administered in 300 of 522 eligible pregnancies (57 %), although this was significantly lower in those with Māori ethnicity (35 %, p = 0.008 versus European ethnicity), or increased parity. Uptake increased over time. All groups surveyed highly preferred (74-86 %) the existing model over alternatives. Service users would highly recommend (95 %) the pharmacy they attended to others eligible for anti-D. Pharmacists were very satisfied with the service and ease of administration but experienced challenges, e.g. service users presenting without the required blood test first and insufficient staffing. Midwife-pharmacist communication was sometimes rated poorly. Courier and pharmacy costs were 3 % and 10 % of the total cost, respectively.

CONCLUSION

Anti-D prescribed by midwives and administered by community pharmacists is convenient for service users, low cost, and the preferred model for service users, midwives and pharmacists. Uptake needs to increase and focus on equity.

Evaluation of the clinical effect of a nationwide implementation of targeted routine antenatal anti-D prophylaxis in Denmark

BACKGROUND

In 2010, Denmark was the first country to implement a targeted routine antenatal anti-D prophylaxis (tRAADP) program, offering fetal RHD genotyping to all nonimmunized D negative pregnant women. The program represented a shift from only postnatal prophylaxis to a combined antenatal and postnatal prophylaxis. This study aimed to evaluate the clinical effect of tRAADP in Denmark.

STUDY DESIGN AND METHODS

This nationwide registry-based cohort study included all D negative women who gave birth between 2004-2020, identified through the National Medical Birth Register and the Departments of Clinical Immunology in Denmark. The clinical effect of tRAADP was assessed by comparing the incidence of new D immunization between 2004-2009 (non-tRAADP-cohort) and 2011-2018 (tRAADP-cohort).

RESULTS

A total of 282 women were D immunized during pregnancy between 2004-2009 (non-tRAADP-cohort), and 167 between 2011-2018 (tRAADP-cohort). The incidence of new D immunization decreased from 0.46% (95% CI 0.41-0.52) in the non-tRAADP-cohort to 0.22% (95% CI 0.19-0.25) in the tRAADP-cohort. The risk reduction was statistically significant p < 0.001. Notably, in the tRAADP cohort 0.1% (95% CI 0.08-0.12) of new D immunizations occurred before the time of antenatal prophylaxis.

DISCUSSION

tRAADP significantly reduced the incidence of new D immunization by more than half, thus demonstrating the expected effect. However, even with full adherence to the current program, some women with early fetomaternal hemorrhage (FMH) were still at risk. Future studies may evaluate the impact of administering an additional tRAADP dose earlier in the second trimester to prevent this.

Why do RhD negative pregnant women still become anti-D immunized despite prophylaxis with anti-D immunoglobulin?

Maternal allo-anti-D in RhD negative pregnant women may cause mild to severe hemolytic disease of the fetus and newborn. Although several other antibodies may also destroy red blood cells of the fetus and newborn, preventive measures with anti-D immunoglobulin are only available for D antigen. Targeted antenatal care together with postpartum prophylaxis with anti-D immunoglobulin has significantly reduced the D-alloimmunization risk. Potentially sensitizing events like trauma to the pregnant abdomen, vaginal bleeding, and amniocentesis may lead to fetomaternal hemorrhage and necessitate additional doses. Despite comprehensive programs with these targeted measures, allo-anti-D is still the most common reason for severe hemolytic disease of the fetus and newborn. Where do we fail then? Here, in this review, I would therefore like to discuss the reasons for D-alloimmunizations hoping that the greater focus will pave the way for further reduction in the number of pregnancy-related allo-anti-Ds.

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

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

Guideline No. 448: Prevention of Rh D Alloimmunization

OBJECTIVE

This guideline provides recommendations for the prevention of Rh D alloimmunization (isoimmunization) in pregnancy, including parental testing, routine postpartum and antepartum prophylaxis, and other clinical indications for prophylaxis. Prevention of red cell alloimmunization in pregnancy with atypical antigens (other than the D antigen), for which immunoprophylaxis is not currently available, is not addressed in this guideline.

TARGET POPULATION

All Rh D-negative pregnant individuals at risk for Rh D alloimmunization due to potential exposure to a paternally derived fetal Rh D antigen.

OUTCOMES

Routine postpartum and antepartum Rh D immunoprophylaxis reduces the risk of Rh D alloimmunization at 6 months postpartum and in a subsequent pregnancy.

BENEFITS, HARMS, AND COSTS

This guideline details the population of pregnant individuals who may benefit from Rho(D) immune globulin (RhIG) immunoprophylaxis. Thus, those for whom the intervention is not required may avoid adverse effects, while those who are at risk of alloimmunization may mitigate this risk for themselves and/or their fetus.

EVIDENCE

For recommendations regarding use of RhIG, Medline and Medline in Process via Ovid and Embase Classic + Embase via Ovid were searched using both the trials and observational studies search strategies with study design filters. For trials, the Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects via Ovid were also searched. All databases were searched from January 2000 to November 26, 2019. Studies published before 2000 were captured from the grey literature of national obstetrics and gynaecology specialty societies, luminary specialty journals, and bibliographic searching. A formal process for the systematic review was undertaken for this update, as described in the systematic review manuscript published separately.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the SOGC's modified GRADE approach. See Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

The intended users of this guideline include prenatal care providers such as obstetricians, midwives, family physicians, emergency room physicians, and residents, as well as registered nurses and nurse practitioners.

TWEETABLE ABSTRACT

An updated Canadian guideline for prevention of Rh D alloimmunization addresses D variants, cffDNA for fetal Rh type, and updates recommendations on timing of RhIG administration.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Application of anti-D immunoglobulin in D-negative pregnant women in China

This article summarizes the current situation of anti-D immunoglobulin (anti-D-Ig) use in RhD-negative pregnant women at home and abroad. The article describes the concept, research and development history, and domestic and foreign applications of anti-D-Ig and points out that anti-D-Ig has not been widely used in China, mainly due to reasons such as unavailability in the domestic market and non-standard current application strategies. The article focuses on analyzing the genetic and immunological characteristics of RhD-negative populations in China. The main manifestations were that the total number of hemolytic disease of the newborn (HDN) relatively high and D variant type. In particular, there are more Asian-type DEL, the importance of clinical application of anti-D-Ig was pointed out, and its antibody-mediated immunosuppressive mechanism was analyzed, which mainly includes red blood cell clearance, epitope blocking/steric hindrance, and Fc γ R Ⅱ B receptor mediated B cell inhibition, anti-D-Ig glycosylation, etc.; clarify the testing strategies of RhD blood group that should be adopted in response to the negative initial screening of pregnant and postpartum women; this article elaborates on the necessity of using anti-D-Ig in RhD-negative mothers after miscarriage or miscarriage, as well as the limitations of its application both domestically and internationally. It also proposes a solution strategy for detecting RhD blood group incompatibility HDFN as early as possible, diagnosing it in a timely manner, and using anti-D-Ig for its prevention and treatment. If the DEL gene is defined as an Asian-type DEL, anti-D-Ig prophylaxis in women would be unnecessary. Finally, based on the specificity of RhD-negative individuals, the article looks forward to the application trend of anti-D-Ig in China. It also called for related drugs to be listed in China as soon as possible and included in medical insurance.