Search

Objectives: To examine local patient safety events related to the administration of anti-Rh(D) immune globin (RhIG) during pregnancy, and to follow-up with targeted educational intervention to improve knowledge of this process., Background: Administration RhIG is established treatment for the prevention of haemolytic disease of the foetus and newborn (HDFN). However, patient safety events in relation to its correct use continue to occur., Methods: A retrospective audit of patient safety events related to RhIG administration during pregnancy was performed. Targeted educational intervention in the form of PowerPoint® presentation were given to nursing staff, laboratory staff and physicians and evaluated with pre- and post-tests using multiple-choice questions given immediately before and after the presentation., Results: An annual incidence of 0.24% of patient safety events related to the administration of RhIG during pregnancy was found. These events were mostly in the preanalytical phase, for example mislabelled samples or samples for D-rosette/Kleihauer-Betke testing drawn from the baby, not the mother. Using Bayesian analysis, the probability of positive effect for the targeted educational intervention was 100% with a median improved score of 29%. This was compared with a control group using standard curriculum education intervention based on the current curriculum for nursing, laboratory and medical students which showed a median improved score of only 4.4%., Conclusions: Administration of RhIG during pregnancy is a multistep process involving health care professionals of several disciplines providing opportunities to enhance the curriculum for nursing, laboratory and medical students and to ensure on-going education., (© 2023 The Authors. Transfusion Medicine published by John Wiley & Sons Ltd on behalf of British Blood Transfusion Society.)

Objectives: To reduce the risk of RhD alloimmunization during the last trimester of pregnancy, a targeted routine antenatal anti-D prophylaxis (RAADP) programme was implemented in Norway in 2016. Here, we present and discuss our experience with the nationwide implementation of the programme, and report sample uptake and preliminary data of de novo anti-D in pregnancy., Background: The targeted RAADP was advised by the academic community and evaluated by the health authorities. A National Working Group has conducted the implementation in the transfusion services and contributed to organise the administration of the antenatal anti-D prophylaxis. Fetal RhD type is determined by non-invasive prenatal testing at gestational week 24, and anti-D prophylaxis is administrated at gestational week 28 only to women with RhD positive fetuses., Methods: We describe the implementation process of targeted RAADP in Norway. The sample uptake is calculated by comparing the number of fetal RHD screens with the expected number of samples., Results: The sample uptake shows regional variations: 88%-100% after 3 years. Promising decrease in de novo anti-D detected during pregnancy is observed., Conclusions: Nationwide targeted RAADP is implemented and included in the Norwegian maternity care programme. Compliance to sample uptake should further improve in some regions. A remaining issue to fulfil is the documentation of the accuracy of the fetal RHD-typing at all sites. Post-natal prophylaxis will then be guided by the fetal RHD result. Dedicated registries will ensure data to evaluate the expected reduction in pregnancy-related RhD immunisations, which is the final success criterion of the programme., (© 2021 British Blood Transfusion Society.)

The aim of this study was to determine how many UK maternity units have implemented National Institute for Clinical Excellence (NICE) guidance for routine antenatal anti-D prophylaxis (RAADP). In May 2002, the NICE recommended a policy of RAADP for RhD-negative pregnant women. The policy has the potential to reduce maternal sensitization and prevent deaths from haemolytic disease of the foetus and newborn, but implementation entails considerable clinical, financial and organizational challenges. A postal survey of all 324 UK maternity units was completed in 2005.Responses were received from 91% of units (294 of 324). RAADP was offered by 220 of 294 (75%) and in England and Wales 19% of those offered a single-dose regime. At 12% of maternity units, routine paternal blood group testing was offered. For 84% of maternity units, staff education was offered at the time of implementation. Written patient information was provided at 97% of maternity units and 147 of 217 (69%) returned a copy. We received 60 different leaflets. Three years after NICE guidance was issued, one in four maternity units did not offer RAADP. Among those that do offer RAADP, practice with regard to anti-D administration, paternal testing, provision of written information and staff education varied. Unit and clinician level research is required to understand why.

The aim of this study was to determine the compliance rates for women being offered routine antenatal anti-D prophylaxis in two obstetric units in the UK. Haemolytic disease of the newborn (HDN) is a potentially serious condition that can result in substantial morbidity and sometimes death. Current guidelines recommend that 500 IU anti-D immunoglobulin G (IgG) should be offered to all non-sensitized RhD-negative women at 28 and 34 weeks' gestation in order to prevent the risk of RhD sensitization in pregnancy. Implementing guidance, however, remains a challenge. We conducted a retrospective audit of 207 RhD-negative, non-sensitized pregnant women attending obstetric units during 2004 to assess compliance with national guidance on the provision of antenatal anti-D prophylaxis. Informed consent for routine antenatal anti-D prophylaxis was documented for 185 of these women. In total, 86.5% of women received the two doses of anti-D IgG. The majority of women received their first and second doses within 1 week of 28 and 34 weeks' gestation (87.0 and 86.0%, respectively). Accurate records of prophylactic anti-D IgG were maintained and updated. This audit demonstrates that the level of patient compliance with the two-dose regimen was high.

The serological differentiation of weak D from partial D, D-negative and D-positive is not always unequivocal. Therefore, sequencing of the RHD gene is required in some cases. Very recently, several new differences between RHD and RHCE have been identified which permitted us to design primers close to the exon/intron boundaries of the RHD-exons. We evaluated these primers in 83 D-positive and 18 D-negative blood donors and applied the new method for the characterization of the RHD gene in six individuals with weak D phenotype. The amplification reactions were concordant with serological findings in 100 of 101 donors (99.0%). In one D-positive donor the PCR for exons 2 and 5 gave a negative result, while the sequence of the remaining eight exons was unchanged. By sequencing samples with very weak D serological reactions, we identified weak D type 4.2.2 and weak D type 15, both previously reported to be associated with anti-D-alloimmunization. Consequently, we recommended the selection of D-negative blood in the weak D type 4.2.2 patient, and the provision of Rh prophylaxis for pregnant women with weak D type 15. In summary, a new RHD sequencing method was developed which can be applied if serological reactions are inconclusive.

Anti-RhD immunoglobulin was administered to RhD-negative women based on estimates of fetal bleed size obtained using a direct immunofluorescence flow cytometric technique employing a FITC-conjugated monoclonal human anti-D (BRAD 3). The effectiveness of the dose administered was assessed by (i) measuring the fraction of RhD-positive fetal cells in the maternal circulation at d0, and between d2 and d10 post RhD Ig administration, (ii) quantifying the amount of anti-D detectable in maternal plasma following RhD Ig injection in the perinatal period and (iii) assessing maternal serum for the presence of immune anti-D in follow-up samples taken 3 months to 3 years after delivery. Fifty-four women were assessed, 29 having fetal bleeds in excess of 4 mL. Follow-up samples were received from 20/29 mothers after RhD Ig administration; 43-99% and 69-99% of fetal cells had been cleared by d2/3 and d5/6, respectively, in 14/20 mothers, whereas less than 50% had been cleared in the remaining mothers. Long-term follow-up samples were obtained from eight of the 29 mothers (four with bleeds >/=20 mL, two with bleeds >95 mL): none had detectable anti-D in the serum 4 months to 3 years after delivery despite the persistence of up to 36% fetal RhD-positive cells in the maternal circulation six days after delivery.

A dynamic model of the action of anti-D immunoglobulin in effecting clearance of Rh D-positive red cells from the circulation of D-negative subjects is presented. The pharmacokinetics of the redistribution of anti-D between injection site, intravascular and extravascular spaces following either intramuscular or intravenous administration is included, also the reaction of anti-D with D-positive red cells in the intravascular space and subsequent circulatory clearance of antibody-coated cells. Numerical computer modelling methods have been used to obtain solutions of the model, using kinetic rate constants which have been derived from previously published experimental data. Selected solutions are presented, chosen for their relevance to (i) clinical situations in which anti-D is used to prevent Rh D immunization of D-negative subjects and (ii) determination of some of the properties of anti-D antibodies which are important for effecting circulatory clearance of D-positive red cells.

Routine antenatal Rh immunoprophylaxis would substantially increase the use of anti-D Ig in the U.K. As availability of anti-D Ig is one factor influencing a decision to introduce routine antenatal prophylaxis, a trial was undertaken to test the efficacy of a lower dose of anti-D Ig than that used in earlier studies. RhD-negative primigravidae were randomized as controls or recipients of two doses of 250iu of anti-D Ig given at 28 and 34 weeks gestation. Blood samples were tested at delivery and at 6 months postpartum for the presence of immune anti-D, and again later if results were equivocal. Nine (1.5%) out of 595 control patients had immune anti-D at follow-up at 6 months and later; 4 (0.78%) of 513 treated women were immunized. It was concluded that, while two doses of 250iu of anti-D Ig may reduce alloimmunization, they are not as effective as two doses of 500iu in a previous trial.