This guideline gives recommendations for serological and molecular blood grouping and red cell antibody testing in pregnancy to predict the potential for, and where possible prevent, haemolytic disease of the fetus and newborn (HDFN). It complements the more clinical 2014 RCOG guideline no.65 - Management of women with Red Cell Antibodies during Pregnancy. Timing of routine antenatal ABO/D testing and screening for red cell antibodies is covered, and BCSH compatibility testing guidelines 2012 are referenced for details of this testing and for requirements for identification of antibodies, if detected.

The application of non-invasive molecular testing to genotype (and predict the fetal phenotype) using cell free fetal DNA is discussed, both in the context of alloimmunised pregnancies and for screening all D negative pregnant women to allow targeting of anti-D Ig prophylaxis to those carrying a D positive fetus. The relevance and application of paternal testing is also discussed.

There are algorithms for the monitoring of women with red cell antibodies of specificities known to have potential to cause significant HDFN (anti-D, anti-c and anti-K), covering frequency of testing, measurement of antibody concentration (by quantification or titration as appropriate), referral to a fetal medicine specialist, and follow-up required post-delivery.

The need for effective communication between all health professionals involved is highlighted, to ensure that the strategy adopted to monitor each affected pregnancy is clear, as there are different options for monitoring once regular MCA Doppler is established, and depending on information regarding antigen status of the fetus. The potential for red cell antibodies other than anti-D, anti-c and anti-K to cause HDFN is considered. The risks of confusing immune anti-D in pregnancy for passive anti-D Ig (and vice versa) are highlighted and an algorithm is provided for testing and reviewing clinical history in these circumstances, to ensure that appropriate anti-D Ig prophylaxis / monitoring of the fetus takes place in order to minimise the risk of sensitisation to the D antigen or of anti-D related HDFN going untreated.

Declaration of Interests

The BSH paid the expenses incurred during the writing of this guidance. None of the authors had conflicts of interest to declare. All authors have made a declaration of interests to the BSH and Task Force Chairs which may be viewed on request.