Results of noninvasive prenatal <i>RHD</i> testing in Gestation Week 25 are not affected by maternal body mass index

Jakobsen, Marianne Antonius; Rosbach, Hanne; Dellgren, Christoffer; Yazer, Mark H.; Sprogøe, Ulrik

doi:10.1111/trf.14827

Cited by 3 publications

(1 citation statement)

References 18 publications

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“…If both the RHD and DYS‐14 tests provide negative results prior to the 25th gestational week, additional testing after this term will be performed. A recent study [49] demonstrated that RHD testing performed in the 25th gestational week and later is both reliable and accurate and it is not influenced by maternal BMI.…”

Section: Discussionmentioning

confidence: 99%

Optimization of diagnostic strategy for non‐invasive cell‐free foetal RHD determination from maternal plasma

et al. 2021

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Background and objectives The aim of the study was to optimize routine non‐invasive prenatal detection of fetal RHD gene from plasma of RhD‐negative pregnant women (the median of gestational age was 25 weeks, range 10–38) to detect RhD materno‐fetal incompatibility and to avoid the redundant immunoprophylaxis. Materials and methods Initially only one exon of RHD gene (exon 10) was investigated in 281 plasma samples (144 verified after delivery), in the second phase three RHD exons (5, 7, 10) were analyzed in 246 samples of plasma and maternal genomic DNA (204 verified) by real‐time PCR method. Detection of Y‐chromosomal sequence DYS‐14 and five X‐chromosomal insertion/deletion polymorphisms was used to confirm the fetal cfDNA detectability in plasma. Specific polymorphisms in RHD gene were detected by sequence‐specific primer PCR in nine samples. Results When only the RHD exon 10 was tested, 2·8% of verified samples were false positive and 3·5% false negative. With three RHD exons (5, 7, 10) and maternal genomic DNA testing, only one case was false negative (0·5%). Nine samples were inconclusive due to RHD‐positive results in maternal genomic DNA. These samples were analyzed for specific mutations in RHD gene. Combination of both methods for fetal cfDNA verification succeeded in 75% of tested group. Conclusion Implementation of analysis of three RHD exons and maternal genomic DNA to routine practice lowers dramatically the ratio of false positive and negative results. This method enables more accurate determination of fetal RHD status with the reduction of unnecessary medical care and RhD immunoprophylaxis.

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Section: Discussionmentioning

confidence: 99%

Optimization of diagnostic strategy for non‐invasive cell‐free foetal RHD determination from maternal plasma

et al. 2021

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Targeted Rhesus immunoglobulin for RhD‐negative women undergoing an induced abortion: A clinical pilot study

Jensen

Damkjaer

Clausen

et al. 2019

Acta Obstet Gynecol Scand

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IntroductionThe aim of this clinical pilot study was to examine the accuracy of noninvasive fetal RHD genotyping in early pregnancy (8+0 to 11+6 weeks) and to clarify whether targeted administration of Rhesus immunoglobulin (RhIg) is possible for women undergoing an induced abortion such that unnecessary injections can be avoided. The study examines the correlation between gestational age and the amount of cell‐free fetal DNA in maternal plasma, the fetal fraction of DNA and whether transportation time or body mass index affects these parameters.Material and methodsFifty‐two RhD‐negative women undergoing a surgically induced abortion were included. A maternal blood sample was collected prior to the abortion and a tissue sample was collected from the placental part of the abortion material after the intervention. Fetal RhD type was determined by PCR analysis of cell‐free fetal DNA extracted from maternal plasma and on DNA from the tissue sample, with the latter providing a reference standard. Copies of RHD/mL were determined on RHD‐positive samples and the fetal fraction of DNA was calculated.ResultsWe demonstrated complete concordance between results from plasma and tissue, with 31 RhD‐positive and 21 RhD‐negative samples, corresponding to 40% being RhD‐negative, specificity 100% [95% confidence interval (CI) 88.8‐100] and sensitivity 100% (95% CI 83.9‐100). We found no significant correlation between gestational age and the amount or the fraction of cell‐free fetal DNA in maternal plasma, nor did we find that transportation time or BMI significantly affected these factors in this setup.ConclusionsFetal RHD genotyping can be accurately performed from the 8th week of gestation and unnecessary injections of RhIg can be avoided for women undergoing an induced abortion. A larger study is needed to determine a more accurate sensitivity for the analysis early in pregnancy.

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Antenatal RHD screening to guide antenatal anti-D immunoprophylaxis in non-immunized D– pregnant women

Clausen

2024

Immunohematology

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In pregnancy, D– pregnant women may be at risk of becoming immunized against D when carrying a D+ fetus, which may eventually lead to hemolytic disease of the fetus and newborn. Administrating antenatal and postnatal anti-D immunoglobulin prophylaxis decreases the risk of immunization substantially. Noninvasive fetal RHD genotyping, based on testing cell-free DNA extracted from maternal plasma, offers a reliable tool to predict the fetal RhD phenotype during pregnancy. Used as a screening program, antenatal RHD screening can guide the administration of antenatal prophylaxis in non-immunized D– pregnant women so that unnecessary prophylaxis is avoided in those women who carry a D– fetus. In Europe, antenatal RHD screening programs have been running since 2009, demonstrating high test accuracies and program feasibility. In this review, an overview is provided of current state-of-the-art antenatal RHD screening, which includes discussions on the rationale for its implementation, methodology, detection strategies, and test performance. The performance of antenatal RHD screening in a routine setting is characterized by high accuracy, with a high diagnostic sensitivity of ≥99.9 percent. The result of using antenatal RHD screening is that 97–99 percent of the women who carry a D– fetus avoid unnecessary prophylaxis. As such, this activity contributes to avoiding unnecessary treatment and saves valuable anti-D immunoglobulin, which has a shortage worldwide. The main challenges for a reliable noninvasive fetal RHD genotyping assay are low cell-free DNA levels, the genetics of the Rh blood group system, and choosing an appropriate detection strategy for an admixed population. In many parts of the world, however, the main challenge is to improve the basic care for D– pregnant women.

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Results of noninvasive prenatal RHD testing in Gestation Week 25 are not affected by maternal body mass index

Abstract: The accuracy of NIP RHD testing performed in Gestation Week 25 does not depend on maternal BMI in the 12th gestation week.

Cited by 3 publications

References 18 publications

Optimization of diagnostic strategy for non‐invasive cell‐free foetal RHD determination from maternal plasma

Optimization of diagnostic strategy for non‐invasive cell‐free foetal RHD determination from maternal plasma

Targeted Rhesus immunoglobulin for RhD‐negative women undergoing an induced abortion: A clinical pilot study

Antenatal RHD screening to guide antenatal anti-D immunoprophylaxis in non-immunized D– pregnant women

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