No. 343-Routine Non-invasive Prenatal Prediction of Fetal RHD Genotype in Canada: The Time is Here


      The optimal management of the D-negative pregnant woman is now based on the non-invasive antenatal prediction of fetal D-blood group by cell-free DNA (cfDNA) in maternal plasma, with targeted prophylaxis for women carrying RHD-positive fetuses. This provides the optimal care for D-negative pregnant women and has been adopted as the standard approach in a growing number of countries around the world. This paper is the result of a consensus meeting of the Canadian National Rh Working Group, an interdisciplinary group formed to review the current status of fetal RHD genotyping based on cfDNA in Canada. The group, in collaboration with the SOGC Genetics committee, reviewed the benefits and challenges of implementing RHD genotyping with targeted prophylaxis in the context of the existing routine antenatal anti D prophylaxis program in Canada. The following summary statements and recommendations are based on this review.

      Summary Statements

      • 1.
        Non-invasive antenatal determination of fetal RHD genotype by cell-free DNA is highly accurate with sensitivities above 99% and very few false-negative results (II-2).
      • 2.
        While the risks of Rh immune globulin exposure are exceptionally low, it is no longer considered appropriate to treat all D-negative pregnant women with human plasma derivatives when there are no benefits to her or to the fetus in a substantial percentage of cases (II-2).
      • 3.
        Implementation of non-invasive fetal RHD genotyping with targeted routine antenatal anti-D prophylaxis would enable up to 40% of D-negative women to avoid use of Rh immune globulin (II-2).
      • 4.
        Fetal RHD genotyping is feasible as early as 10 weeks’ gestation and earlier testing is preferable as it allows for targeted prophylaxis for women with sensitizing events prior to 28 weeks’ gestation (II-2).
      • 5.
        Implementation of non-invasive fetal RHD genotyping with selective prophylaxis requires interdisciplinary collaboration (clinical and laboratory) as well as the endorsement of provincial ministries of health (III).


      • 1.
        The current optimal management of the D-negative pregnant woman is based on the prediction of the fetal D-blood group by cell-free DNA in maternal plasma with targeted antenatal anti-D prophylaxis. This approach should be adopted in Canada (II-2A).
      • 2.
        While various algorithms of implementation of fetal RHD genotyping have been described, a model positioned in the first trimester appears to be most in alignment with the existing Canadian antenatal anti-D prophylaxis program and should be endorsed (II-2A).
      • 3.
        While the risk of a false-negative result with RHD genotyping is very small and the benefits of knowing the fetal RHD status in terms of compliance with prophylaxis seem to outweigh the risks, the chance of immunization is not zero. Quality control at a laboratory and clinical level should be of utmost priority in program planning (II-3A).


      CBS (Canada blood sevices), cfDNA (cell-free DNA), FMH (fetomaternal hemorrhage), FN (false-negative), FP (false-positive), HDFN (Hemolytic disease of the fetus and newborn), PCR (polymerase chain reaction), RAADP (routine antenatal anti-D prophylaxis), RHD (the gene that determines the expression of the D antigen), RhD (Rhesus D antigen positive), RhIG (Rh (D) immunoglobulin)
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        • Bowman J.M.
        The prevention of Rh immunization.
        Transfus Med Rev. 1988; 2: 129-150
        • Moise Jr., K.J.
        Management of rhesus alloimmunization in pregnancy.
        Obstet Gynecol. 2002; 100: 600-611
        • Kumar S.
        • Regan F.
        Management of pregnancies with RhD alloimmunisation.
        BMJ. 2005; 330: 1255-1258
        • Urbaniak S.J.
        The scientific basis of antenatal prophylaxis.
        Br J Obstet Gynaecol. 1998; 105: 11-18
        • Bowman J.M.
        Controversies in Rh prophylaxis. Who needs Rh immune globulin and when should it be given?.
        Am J Obstet Gynecol. 1985; 151: 289-294
        • Hughes R.G.
        • Craig J.I.
        • Murphy W.G.
        • et al.
        Causes and clinical consequences of Rhesus (D) haemolytic disease of the newborn: a study of a Scottish population, 1985-1990.
        Br J Obstet Gynaecol. 1994; 101: 297-300
        • Bowman J.M.
        • Pollock J.M.
        • Penston L.E.
        Fetomaternal transplacental hemorrhage during pregnancy and after delivery.
        Vox Sang. 1986; 51: 117-121
        • Lee D.
        • Contreras M.
        • Robson S.C.
        • et al.
        Recommendations for the use of anti-D immunoglobulin for Rh prophylaxis. British Blood Transfusion Society and the Royal College of Obstetricians and Gynaecologists.
        Transfus Med. 1999; 9: 93-97
        • Tiblad E.
        • Westgren M.
        • Pasupathy D.
        • et al.
        Consequences of being Rhesus D immunized during pregnancy and how to optimize new prevention strategies.
        Acta Obstet Gynecol Scand. 2013; 92: 1079-1085
        • Crowther C.A.
        • Keirse M.J.
        Anti-D administration in pregnancy for preventing rhesus alloimmunisation.
        Cochrane Database Syst Rev. 2000; : CD000020
        • Chilcott J.
        • Lloyd Jones M.
        • Wight J.
        • et al.
        A review of the clinical effectiveness and cost-effectiveness of routine anti-D prophylaxis for pregnant women who are rhesus-negative.
        Health Technol Assess. 2003; 7 (iii–62)
        • Woolf S.H.
        • Battista R.N.
        • Anderson G.M.
        • et al.
        Assessing the clinical effectiveness of preventive maneuvers: analytic principles and systematic methods in reviewing evidence and developing clinical practice recommendations. A report by the Canadian Task Force on the Periodic Health Examination.
        J Clin Epidemiol. 1990; 43: 891-905
        • Fung Kee Fung K
        • Eason E.
        • Crane J.
        • et al.
        Prevention of Rh alloimmunization.
        J Obstet Gynaecol Can. 2003; 25: 765-773
        • van der Schoot C.E.
        • Hahn S.
        • Chitty L.S.
        Non-invasive prenatal diagnosis and determination of fetal Rh status.
        Semin Fetal Neonatal Med. 2008; 13: 63-68
        • Lo Y.M.
        • Corbetta N.
        • Chamberlain P.F.
        • et al.
        Presence of fetal DNA in maternal plasma and serum.
        Lancet. 1997; 350: 485-487
        • Akolekar R.
        • Finning K.
        • Kuppusamy R.
        • et al.
        Fetal RHD genotyping in maternal plasma at 11-13 weeks of gestation.
        Fetal Diagn Ther. 2011; 29: 301-306
        • Chitty L.S.
        • Finning K.
        • Wade A.
        • et al.
        Diagnostic accuracy of routine antenatal determination of fetal RHD status across gestation: population based cohort study.
        BMJ. 2014; 349: g5243
        • Soothill P.W.
        • Finning K.
        • Latham T.
        • et al.
        Use of cffDNA to avoid administration of anti-D to pregnant women when the fetus is RhD-negative: implementation in the NHS.
        BJOG. 2015; 122: 1682-1686
        • Clausen F.B.
        • Christiansen M.
        • Steffensen R.
        • et al.
        Report of the first nationally implemented clinical routine screening for fetal RHD in D- pregnant women to ascertain the requirement for antenatal RhD prophylaxis.
        Transfusion. 2012; 52: 752-758
        • Finning K.
        • Martin P.
        • Summers J.
        • et al.
        Effect of high throughput RHD typing of fetal DNA in maternal plasma on use of anti-RhD immunoglobulin in RhD negative pregnant women: prospective feasibility study.
        BMJ. 2008; 336: 816-818
        • Manzanares S.
        • Entrala C.
        • Sanchez-Gila M.
        • et al.
        Noninvasive fetal RhD status determination in early pregnancy.
        Fetal Diagn Ther. 2014; 35: 7-12
        • Tounta G.
        • Vrettou C.
        • Kolialexi A.
        A multiplex PCR for non-invasive fetal RHD genotyping using cell-free fetal DNA.
        In Vivo. 2011; 25: 411-417
        • Finning K.M.
        • Martin P.G.
        • Soothill P.W.
        • et al.
        Prediction of fetal D status from maternal plasma: introduction of a new noninvasive fetal RHD genotyping service.
        Transfusion. 2002; 42: 1079-1085
        • Finning K.
        • Martin P.
        • Summers J.
        • et al.
        Fetal genotyping for the K (Kell) and Rh C, c, and E blood groups on cell-free fetal DNA in maternal plasma.
        Transfusion. 2007; 47: 2126-2133
        • Kent J.
        • Farrell A.M.
        • Soothill P.
        Routine administration of Anti-D: the ethical case for offering pregnant women fetal RHD genotyping and a review of policy and practice.
        BMC Pregnancy Childbirth. 2014; 14: 87
        • Smith A.
        • Fiddler J.
        • Walby K.
        • et al.
        Blood donation and institutional trust: risk, policy rhetoric, and the men who have sex with men lifetime deferral policy in Canada.
        Can Rev Sociol. 2011; 48: 369-389
        • Kenny-Walsh E.
        Clinical outcomes after hepatitis C infection from contaminated anti-D immune globulin. Irish Hepatology Research Group.
        N Engl J Med. 1999; 340: 1228-1233
        • Lo Y.M.
        • Tein M.S.
        • Lau T.K.
        • et al.
        Quantitative analysis of fetal DNA in maternal plasma and serum: implications for noninvasive prenatal diagnosis.
        Am J Hum Genet. 1998; 62: 768-775
        • Beulen L.
        • Grutters J.P.
        • Faas B.H.
        • et al.
        The consequences of implementing non-invasive prenatal testing in Dutch national health care: a cost-effectiveness analysis.
        Eur J Obstet Gynecol Reprod Biol. 2014; 182: 53-61
        • Colin Y.
        • Cherif-Zahar B.
        • Le Van Kim C.
        • et al.
        Genetic basis of the RhD-positive and RhD-negative blood group polymorphism as determined by Southern analysis.
        Blood. 1991; 78: 2747-2752
        • Daniels G.
        Variants of RhD–current testing and clinical consequences.
        Br J Haematol. 2013; 161: 461-470
        • Daniels G.
        • Finning K.
        • Martin P.
        • et al.
        Noninvasive prenatal diagnosis of fetal blood group phenotypes: current practice and future prospects.
        Prenat Diagn. 2009; 29: 101-107
        • van der Schoot C.E.
        • Tax G.H.
        • Rijnders R.J.
        • et al.
        Prenatal typing of Rh and Kell blood group system antigens: the edge of a watershed.
        Transfus Med Rev. 2003; 17: 31-44
        • Wikman A.T.
        • Tiblad E.
        • Karlsson A.
        • et al.
        Noninvasive single-exon fetal RHD determination in a routine screening program in early pregnancy.
        Obstet Gynecol. 2012; 120: 227-234
        • Dziegala M.
        Noninvasive prenatal screening for RHD: the 1st national antenatal directed anti-D prophylaxis program - the Danish Model or a guide to robost prediction of need of Anti-D.
        Sci Ser. 2012; : 160-163
        • de Haas M.
        • van der Ploeg C.P.B.
        • Scheffer P.G.
        • et al.
        A nation-wide fetal RHD screening programme for targeted antenatal and postnatal anti-D.
        ISBT Science Series. 2012; 7: 164-167
        • Tiblad E.
        • Taune Wikman A.
        • et al.
        Targeted routine antenatal anti-D prophylaxis in the prevention of RhD immunisation–outcome of a new antenatal screening and prevention program.
        PLoS One. 2013; 8: e70984
        • Minon J.M.
        • Gerard C.
        • Senterre J.M.
        • et al.
        Routine fetal RHD genotyping with maternal plasma: a four-year experience in Belgium.
        Transfusion. 2008; 48: 373-381
        • Clausen F.B.
        Integration of noninvasive prenatal prediction of fetal blood group into clinical prenatal care.
        Prenat Diagn. 2014; 34: 409-415
        • MacKenzie I.Z.
        • Findlay J.
        • Thompson K.
        • et al.
        Compliance with routine antenatal rhesus D prophylaxis and the impact on sensitisations: observations over 14 years.
        BJOG. 2006; 113: 839-843
        • Pilgrim H.
        • Lloyd-Jones M.
        • Rees A.
        Routine antenatal anti-D prophylaxis for RhD-negative women: a systematic review and economic evaluation.
        Health Technol Assess. 2009; 13 (ix–xi,1–103): iii
        • Koby L.
        • Grunbaum A.
        • Benjamin A.
        • et al.
        Anti-D in Rh(D)-negative pregnant women: are at-risk pregnancies and deliveries receiving appropriate prophylaxis?.
        J Obstet Gynaecol Can. 2012; 34: 429-435
        • Koelewijn J.
        Detection and prevention of pregnancy immunisation: The OPZI-study.
        ([Doctoral Thesis]) University of Amsterdam, 2009
        • Kumpel B.M.
        Efficacy of RhD monoclonal antibodies in clinical trials as replacement therapy for prophylactic anti-D immunoglobulin: more questions than answers.
        Vox Sang. 2007; 93: 99-111
        • Hawk A.F.
        • Chang E.Y.
        • Shields S.M.
        • et al.
        Costs and clinical outcomes of noninvasive fetal RhD typing for targeted prophylaxis.
        Obstet Gynecol. 2013; 122: 579-585
        • Duplantie J.
        • Martinez Gonzales O.
        • Bois A.
        • et al.
        Cost-effectiveness of the management of rh-negative pregnant women.
        J Obstet Gynaecol Can. 2013; 35: 730-740
        • Benachi A.
        • Delahaye S.
        • Leticee N.
        • et al.
        Impact of non-invasive fetal RhD genotyping on management costs of rhesus-D negative patients: results of a French pilot study.
        Eur J Obstet Gynecol Reprod Biol. 2012; 162: 28-32
        • Szczepura A.
        • Osipenko L.
        • Freeman K.
        A new fetal RHD genotyping test: costs and benefits of mass testing to target antenatal anti-D prophylaxis in England and Wales.
        BMC Pregnancy Childbirth. 2011; 11: 5
        • Teitelbaum L.
        • Metcalfe A.
        • Clarke G.
        • et al.
        Costs and benefits of non-invasive fetal RhD determination.
        Ultrasound Obstet Gynecol. 2015; 45: 84-88
        • Neovius M.
        • Tiblad E.
        • Westgren M.
        • et al.
        Cost-effectiveness of first trimester non-invasive fetal RHD screening for targeted antenatal anti-D prophylaxis in RhD-negative pregnant women: a model-based analysis.
        BJOG. 2016; 123: 1337-1346