Management and outcome of pregnancies in women with red cell isoimmunization: a 15-year observational study from a tertiary care university hospital

Management of pregnancies with anti-K alloantibodies and the predictive value of anti-K titration testing

Anti-KEL1 antigen (also referred to as anti-Kell, or anti-K) alloimmunisation is the second most common cause of severe haemolytic disease of the fetus and newborn, after anti-rhesus D antigen, and can cause substantial fetal morbidity and mortality. Both fetal erythropoietic suppression and haemolysis contribute to anaemia. Typically, once a clinically significant alloantibody is identified during pregnancy, antibody titration is performed as a screening test to predict the risk of anaemia and the need for maternal-fetal medicine referral. The titre is a semiquantitative laboratory method based on the underlying principle that increased maternal antibody concentrations are associated with an increased risk of fetal anaemia. Because some studies report that anti-K alloantibodies can lead to severe anaemia even at a low antibody titration, guidelines are inconsistent with respect to the role of titration testing. Some experts recommend maternal-fetal medicine referral and middle cerebral artery Doppler ultrasound without titration testing or with the use of a very low cutoff titre. This Viewpoint evaluates management for pregnancies affected by anti-K alloantibodies and highlights literature regarding the predictive value of anti-K titration testing.

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.

The role of measuring peak systolic velocity of the middle cerebral artery blood flow and anti-K1 titre during pregnancy to detect foetuses with severe anaemia, foetal hydrops, and the requirement of intrauterine transfusion: A systematic review and meta-analysis

The clinical manifestation of foetal anaemia caused by maternal Kell alloantibodies differs from that caused by non-Kell alloantibodies. Severe anaemia develops in the foetus in the early weeks of gestation; therefore, proper management and early intervention are important. A systematic review and meta-analysis was performed to determine whether the anti-K1 titre can determine the sequelae of Kell alloimmunised pregnancies. Prospective and retrospective cohort studies were used to conduct a systematic review following a comprehensive literature search, in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Studies were screened based on a defined set of inclusion and exclusion criteria. A total of 5143 potential articles were identified. Ten studies were used in the meta-analysis of pregnancy outcomes for a specific anti-K1 titre cut-off. The meta-analysis identified statistical significance for intrauterine transfusion (ARD: 0.351; 95 % CI: 0.593-0.109; p-value = 0.004), hydrops (ARD: 0.808; 95 % CI: 1.145-0.472; p-value <0.001), intrauterine foetal death (ARD: 0.938; 95 % CI:1.344 to -0.533; p-value <0.001) and intrauterine transfusion for Doppler middle cerebral artery >1.5 MoM (ARD: 0.381; 95 % CI:1.079 to -0.317; p-value = 0.285). It was concluded that there is no correlation between anti-K1 titre and Kell sensitised pregnancy outcomes, but monitoring the anti-K1 titre is important to manage the pregnancy and it helps clinicians determine the need for intrauterine transfusions. Doppler middle cerebral artery peak systolic velocity is strongly correlated with foetal anaemia and is an efficient routine method for determining the need for intrauterine transfusions in pregnancies affected by anti-K1.

Hemolytic disease of the fetus and newborn-a perspective of immunohematology

BACKGROUND

Hemolytic disease of the fetus and newborn is a public health problem caused by maternal-fetal incompatibility; no prophylaxis is available for most alloantibodies that induce this disease. This study reviews the literature regarding which antibodies are the most common in maternal plasma and which were involved in hemolytic disease of the fetus and newborn.

METHOD

Seventy-five studies were included in this review using a systematic search. Two independent authors identified studies of interest from the PubMed and SciELO databases.

MAIN RESULTS

Forty-four case reports were identified, of which 11 babies evolved to death. From 17 prevalence studies, the alloimmunization rate was 0.17 % with 161 babies receiving intrauterine transfusions and 23 receiving transfusions after birth. From 28 studies with alloimmunized pregnant women (7616 women), 455 babies received intrauterine transfusions and 21 received transfusions after birth.

CONCLUSION

Rh, Kell, and MNS were the commonest blood systems involved. The geographical distribution of studies shows that as these figures vary between continents, more studies should be performed in different countries. Investing in early diagnosis is important to manage the risks and complications of hemolytic disease of the fetus and newborn.

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.

Immunohematological testing and transfusion management of the prenatal patient

The primary indication for immunohematological testing in the prenatal patient is to detect and identify maternal red cell antibodies. If there are antibodies that are expected to hemolyze the fetus' red cells, their strength of reactivity must be tested, and the fetus' antigen status determined. After delivery, testing is performed to assess the extent of fetomaternal hemorrhage, as a large hemorrhage may require other therapeutic interventions. Another major role for immunohematological testing is to select blood components appropriately when intrauterine transfusion is required for fetal anemia resulting from maternal alloimmunization or some other cause. Supplementation with molecular methods has transformed the practice of immunohematology, particularly as it applies to typing for the D antigen of the Rh blood group system. Notwithstanding the advances in testing, close coordination and communication between the transfusion service and the obstetrics service are the foundation for ensuring the finest care for prenatal patients, and for new mothers and their infants. This review describes testing and transfusion practices for prenatal patients, using case presentations to highlight the management of selected immunohematological findings. It also includes a discussion of key patient management topics that are currently unresolved.

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.

Red cell alloimmunization in pregnancy: a study from a premier tertiary care centre of Western India

OBJECTIVE

The study was conducted to determine the frequency of alloimmunization to various blood group antibodies in pregnant women, and the risk of hemolytic disease in the fetus and newborn.

METHODS

All antenatal women, irrespective of the period of gestation or obstetric history, were included, whereas those taking anti-D immune-prophylaxis or with a history of blood transfusion were excluded. Antibody screening and identification were performed using a Bio-Rad ID microtyping system.

RESULTS

Of 2,084 antenatal females, 1,765 were D-antigen positive and 319 D-antigen negative. Sixty-five (3.119%) women alloimmunized. Out of 54 (2.591%) who had sensitized to D-antigen, 11 (0.527%) also sensitized to other antibodies. These 11 alloantibodies identified included: anti-M (n=6; 9.23%), anti-C (n=1; 3.076%), anti-E (n=1; 1.538%), anti-e (n=1; 1.538%), anti-Lewis (a) (n=1; 1.538%), and unspecified antibodies (n=1; 1.538%). Multiple antibodies were seen in four patients that combined: anti-D and anti-C (n=2; 3.076%), anti-e and anti-c (n=1; 1.538%), and anti-D and anti-G (n=1; 1.538%).

CONCLUSION

The rate of alloimmunization in D-antigen-negative women was high. Apart from this, the alloimmunization rate in women with bad obstetric history was very high, at 8.1%. In developing countries such as India, universal antenatal antibody screening, though desirable, may not be justified at present, as the cost and infrastructure required would be immense because of the lower alloimmunization rates in RhD antigen-positive women. However, it is necessary to impose properly formulated protocols to screen pregnant women with bad obstetric history.

Perinatal Outcome of Pregnant Women with RhD Sensitization: A Five-Year Cross-Sectional Study at a Tertiary Care Hospital in Ethiopia

Background

Isoimmunization is a process of immunizing an antigen-negative pregnant individual with a paternally derived fetal antigen. Although the Rh systems contain many antigen subtypes (D, C, c, E, e), the RhD antigen is highly immunogenic. This research aimed to investigate the perinatal Outcome of pregnant women with RhD sensitization at St. Paul's Hospital Millennium Medical College (SPHMMC), Ethiopia.

Methodology

A facility-based retrospective cross-sectional study was conducted on 98 pregnant women with RhD alloimmunization at SPHMMC from September 11, 2016, to September 10, 2021. SPSS 26 was used for data analysis. Descriptive statistics were utilized to assess the perinatal outcome of pregnant women with RhD alloimmunization. Fisher's exact test was used to determine which association, and a P value <0.05 was considered statistically significant.

Results

From the 98 pregnancies (06 - hydropic, 92 - non-hydropic) at high risk for fetal anemia, 45.9% of cases had MCA-PSV above 1.5MoM. Among these, 21.42% of all fetuses received an intrauterine transfusion. Forty-three IUTs were performed in 21 fetuses. The median number of transfusions per fetus was two. About 52.4% of the transfused fetuses had severe anemia, and 28.6% had moderate anemia. Prediction of MCA PSV ≥1.5MOM in diagnosing moderate-severe anemia in pregnant women with RhD sensitization 81%. General neonatal survival of alloimmunizations was 93.8%, 90.5% with IUT, 50% with hydrops fetalis, and 96.7% without hydrops.

Conclusion

This research provides evidence that MCA PSV ≥1.5MoM is modest predictor of moderate-severe anemia in untransfused fetuses. This study was a step toward the development of more extensive and multicenter studies on the Perinatal Outcome of pregnant women with RhD sensitization in Ethiopia. Extra studies are needed to evaluate strategies for estimates of fetal anemia after blood transfusion as a result of the absence of information on the IUT database.

Red blood cell alloimmunization in pregnancy: A 10-year single-center study

Background/Aim. Pregnancy-induced red blood cell (RBC) alloimmunization is important not only because of the possible negative effects on subsequent pregnancy outcomes in case the fetus carries the antigen but also because of the optimal trans-fusion management in cases of obstetric hemorrhage. Timely detection of RBC antibodies is part of testing, prevention, and treatment strategy, aimed at achieving better outcomes for alloimmunized mothers with an affected fetus. The aim of the study was to determine the frequency and specificity of alloantibodies among pregnant women from the South Backa District, Serbia, with special attention to the incidence of anti-D alloantibodies. Methods. A retrospective study was conducted in the Blood Transfusion Institute of Vojvodina and covered the period from January 1, 2010, to December 31, 2019. Screening and antibody identification were performed by an indirect antiglobulin test in gel-microcards (ID-Card Liss/Coombs) with two test RBC (ID-DiaCell I-II screening cells, Bio-Rad, Cressier, Switzerland) on an automated system (IH-500, Bio-Rad). Results. Among 25,694 tested pregnant women, 1.38% were actively immunized, while 1.12% of women acquired antibodies in the current pregnancy. Among 3,622 (14.09%) RhD-negative women, 1.77% produced anti-D antibodies during the ongoing pregnancy. Distribution of anti-body specificity was: anti-D 23.34%, anti-M 11.85%, anti-E 9.41%, anti-K 9.41%, anti-C 5.92%, anti-Fyb 5.92%, anti-c 3.13%, anti-S 3.13%, anti-Lea 3.13%, anti-Leb 3.13%, anti-Cw 1.75%, anti-Jka 1.40%, anti-P 1.05%, anti-Lub 0.70%, anti-Fya 0.35%, autoantibody of undetermined specificity 0.70%, and irregular antibodies of undetermined specificity 15.68%. Conclusion. Immunoglobulin prophylaxis has led to a significant reduction in the frequency of D-alloimmunization among pregnant women in the South Backa District over the last ten years. However, the incidence of anti-D antibodies is still significantly higher than in published data for developed countries. We also identified the other, less commonly present, clinically significant antibodies. There is a need to introduce uniform recommendations for immunohematological testing in pregnancy on the territory of the Republic of Serbia in accordance with modern requirements.

Fetal-maternal incompatibility in the Rh system. Rh isoimmunization associated with hereditary spherocytosis: case presentation and review of the literature

Next to A and B antigens, agglutinogen D exhibits the highest immunogenicity. Following the transfusion of D-positive red blood cells (RBCs), almost 80% of D-negative recipients develop anti-D antibodies (Abs). Subsequently, anti-D immunization further promotes the synthesis of Abs towards other blood group antigens in or outside the Rh system. The D antigen is also involved in 95% of cases of hemolytic disease of the newborn. Transfusions, hemotherapy, grafts, and obstetric history (abortions, ectopic pregnancy, births) are all risk factors for Rh isoimmunization. In the case of ABO compatibility between mother and fetus, Rh-positive fetal RBCs that have reached the maternal bloodstream are not destroyed by group agglutinins, and Rh antigenic sites are not hidden by the maternal immune system. But a Rh-negative mother with a homozygous Rh-positive husband will certainly have a Rh-positive fetus. As it has an irreversible evolution, the Rh isoimmunization once installed cannot be influenced in the sense of decreasing the Ab titer, therefore, injectable globulin has no effect. A particular case was that of a newborn with Rh system incompatibility associated with hereditary spherocytosis The clinical balance at birth reflects the severe jaundice of the female newborn of 3140 g, gestational age 38∕39 weeks, extracted by lower-segment transverse Caesarean section, with a double loop nuchal cord, Apgar score 8. Because the jaundice was severe and atypical (face and upper chest), we considered the possibility of coexistence of hemolytic disease of the newborn by Rh blood group incompatibility associated with hereditary spherocytosis, as it turned out to be true and mentioned. Changes in genes encoding proteins in the structure of the RBC membrane have amplified hemolysis induced by maternal-fetal isoimmunization in the Rh system. Massive hemolysis accentuated by congenital spherocytosis, confirmed later, imposed blood transfusion and dynamic monitoring.

Outcome predictors for maternal red blood cell alloimmunisation with anti-K and anti-D managed with intrauterine blood transfusion

Red blood cell (RBC) alloimmunisation with anti-D and anti-K comprise the majority of cases of fetal haemolytic disease requiring intrauterine red cell transfusion (IUT). Few studies have investigated which haematological parameters can predict adverse fetal or neonatal outcomes. The aim of the present study was to identify predictors of adverse outcome, including preterm birth, intrauterine fetal demise (IUFD), neonatal death (NND) and/or neonatal transfusion. We reviewed the records of all pregnancies alloimmunised with anti-K and anti-D, requiring IUT over 27 years at a quaternary fetal centre. We reviewed data for 128 pregnancies in 116 women undergoing 425 IUTs. The median gestational age (GA) at first IUT was significantly earlier for anti-K than for anti-D (24·3 vs. 28·7 weeks, P = 0·004). Women with anti-K required more IUTs than women with anti-D (3·84 vs. 3·12 mean IUTs, P = 0·036) and the fetal haemoglobin (Hb) at first IUT was significantly lower (51.0 vs. 70.5 g/l, P = 0·001). The mean estimated daily decrease in Hb did not differ between the two groups. A greater number of IUTs and a slower daily decrease in Hb (g/l/day) between first and second IUTs were predictive of a longer period in utero. Earlier GA at first IUT and a shorter interval from the first IUT until delivery predicted IUFD/NND. Earlier GA and lower Hb at first IUT significantly predicted need for phototherapy and/or blood product use in the neonate. In the anti-K group, a greater number of IUTs was required in women with a higher titre. Furthermore, the higher the titre, the earlier the GA at which an IUT was required in both groups. The rate of fall in fetal Hb between IUTs decreased, as the number of transfusions increased. Our present study identified pregnancies at considerable risk of an unfavourable outcome with anti-D and anti-K RBC alloimmunisation. Identifying such patients can guide pregnancy management, facilitates patient counselling, and can optimise resource use. Prospective studies can also incorporate these characteristics, in addition to laboratory markers, to further identify and improve the outcomes of these pregnancies.

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.

20 Years of Follow-up Alloimmunization and Hemolytic Disease in Newborn: Has Anything Changed in the Field Over the Years?

OBJECTIVE

of the study is to research the epidemiological aspects of maternal alloimmunization against erythrocyte antigens of fetuses (AB0, Rhesus, Lewis, Kell, Duffy and others) and to identify the most common types of hemolytic disease of the newborn (HDN) in the West Herzegovina region.

STUDY DESIGN

The 20-year retrospective epidemiological study includes all pregnant women who had been immunologically tested and newborn treated for HDN.

RESULTS

The indirect antiglobulin (IAT) detected antibodies against antigens in 545 (1.8%) pregnant women of the 29 663 who were tested at the Department of Transfusion Medicine. During the 20-year-long study 310 (1.0%) newborn with HDN were treated. Our results indicate that 42% (230/545) of the pregnant women had AB0 immunization. The most common form of HDN is AB0 HDN 64% (199/310), whereas RhD HDN was treated in 19% (59/310) of the newborn infants. ETR was performed on 29 (19%) infants, 21 (72.4%) with AB0 HDN, and 7 (26%) with RhD HDN.

CONCLUSION

This 20-year-long study concludes that, even though there has been significant progress in the prevention of immunization and proactive treatment of HDN, precautionary measures are still required as is the need for gynecologists and obstetricians to be active. The reasons for this are the non-existence of preventive measures for non-RhD immunization, the irregular immunological screening of RhD positive women in pregnancy in the region encompassed by the study in the past few years. The above raises new questions and recommends further research and monitoring of immunization and HDN treatment worldwide.

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.