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. 2025 Dec;120(12):1259-1262.
doi: 10.1111/vox.70107. Epub 2025 Sep 10.

Evaluation of 6 years of fetal RHD screening in Ireland: From implementation to practice

Helen Ryan  1 , Mark Lambert  1 , Sorcha Ní Loingsigh  1 , Richard Hagan  1 , Diarmaid O'Donghaile  1   2
Affiliations

Evaluation of 6 years of fetal RHD screening in Ireland: From implementation to practice

Helen Ryan et al. Vox Sang. 2025 Dec.

Abstract

Background and objectives: The discovery of circulating fetal DNA in maternal plasma enabled non-invasive prenatal testing (NIPT) for targeted anti-D prophylaxis. In 2019, Ireland implemented an in-house test to guide this care. Here, we report 6 years of service.

Materials and methods: Cell-free fetal DNA (cffDNA) was extracted from 1000-μL plasma from pregnant RhD negative women at gestation age (GA) > 11 weeks. Samples were tested in triplicate for RHD by quantitative PCR using a multiplex assay of RHD exons 7 and 10.

Results: Of the 20,099 samples tested, 58.2% were predicted RhD positive and 36.9% were predicted RhD negative. Discrepancies were seen in 52 cases: 7 (0.03%) were predicted RhD negative but cord RhD positive and 45 (0.2%) were predicted RhD positive but cord RhD negative.

Conclusion: This test has ensured that over 7400 women have avoided unnecessary anti-D prophylaxis. There were few discrepant results, with false negatives posing a greater clinical risk due to withheld anti-D, increasing immunization risk. Three were linked to pre-analytical errors prompting procedural changes. Due to the success of fetal RHD screening, cord blood testing has been discontinued in some countries; a practice which could be reviewed in Ireland.

Keywords: NIPT; RHD; anti‐D prophylaxis; cffDNA; qPCR.

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References

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