Maternal Serum Screening for Chromosomal Abnormalities and Neural Tube Defects

Cuckle, Howard

doi:10.1002/9781119676980.ch6

Cited by 3 publications

(5 citation statements)

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“…The methods of validation and calibration described here are similar to those that have been applied successfully to screening for Down syndrome. The use of statistical modelling to predict the performance of Down-syndrome screening protocols has proved to be a sound guide to prospective experience 15 . However, it could be argued that, unlike Down syndrome, PE is the result of multiple interactive causal factors that may not be accounted for fully in the risk-calculation algorithm.…”

Section: Other Approachesmentioning

confidence: 99%

Local validation and calibration of pre‐eclampsia screening algorithms

Cuckle

2019

Ultrasound in Obstet & Gyne

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Section: Other Approachesmentioning

confidence: 99%

Local validation and calibration of pre‐eclampsia screening algorithms

Cuckle

2019

Ultrasound in Obstet & Gyne

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“…Conventional combined serum and ultrasound‐based screening for aneuploidy has been shown to have a lower detection rate and/or higher false‐positive rate than that achievable in singletons 6 . Maternal serum markers are unable to distinguish between monozygotic and dizygotic twins and since most affected pregnancies are dizygotic with one affected fetus, serum marker tests are expected to be less discriminatory than is the case for singleton pregnancies 7 . Conventional screening may also be less effective because assisted reproductive techniques (ARTs) may affect first trimester serum markers such as PAPP‐A and free‐ β HCG levels in a way that mimics Down syndrome 42 .…”

Section: Use Of Cf‐dna To Screen For Aneuploidymentioning

confidence: 99%

“…Illustration constructed from material provided by Natera, Inc [Colour figure can be viewed at wileyonlinelibrary.com] dizygotic with one affected fetus, serum marker tests are expected to be less discriminatory than is the case for singleton pregnancies. 7 Conventional screening may also be less effective because assisted reproductive techniques (ARTs) may affect first trimester serum markers such as PAPP-A and free-β HCG levels in a way that mimics Down syndrome. 42 The serum correction factors used for ART pregnancies may be imprecise and therefore further compound the error in the analysis of twin gestations.…”

Section: Use Of Cf-dna To Screen For Aneuploidymentioning

confidence: 99%

“…Maternal agespecific risks for fetal trisomy 21 are not increased, 5 but traditional screening tests have been less effective for women with twin pregnancies. 6,7 Women with twin pregnancies may have been more reluctant to undergo invasive testing (chorionic villus biopsy [CVS] or amniocentesis) as a result of studies that have indicated increased procedure-related risks of pregnancy loss. [8][9][10] Multiple pregnancies are therefore common, associated with a complex set of adverse outcomes, and management has been hampered by late gestational age and less acceptable screening and diagnostic options.…”

Section: Introductionmentioning

confidence: 99%

“…Although only a minority of twin pregnancies are monochorionic, they account for a high portion of the perinatal morbidity and mortality. Maternal age‐specific risks for fetal trisomy 21 are not increased, 5 but traditional screening tests have been less effective for women with twin pregnancies 6,7 . Women with twin pregnancies may have been more reluctant to undergo invasive testing (chorionic villus biopsy [CVS] or amniocentesis) as a result of studies that have indicated increased procedure‐related risks of pregnancy loss 8–10 .…”

Section: Introductionmentioning

confidence: 99%

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Non‐invasive prenatal testing in the management of twin pregnancies

Benn

Rebarber

2021

Prenatal Diagnosis

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Twin pregnancies are common and associated with pregnancy complications and adverse outcomes. Prenatal clinical management is intensive and has been hampered by inferior screening and less acceptable invasive testing. For aneuploidy screening, meta-analyses show that non-invasive prenatal testing (NIPT) through analysis of cell-free DNA (cf-DNA) is superior to serum and ultrasound-based tests.The positive predictive value for NIPT is driven strongly by the discriminatory power of the assay and only secondarily by the prior risk. Uncertainties in a priori risks for aneuploidies in twin pregnancies are therefore of lesser importance with NIPT.Additional information on zygosity can be obtained using NIPT. Establishing zygosity can be helpful when chorionicity was not reliably established early in pregnancy or where the there is a concern for one versus two affected fetuses. In dizygotic twin pregnancies, individual fetal fractions can be measured to ensure that both values are satisfactory. Vanishing twins can be identified by NIPT. Although clinical utility of routinely detecting vanishing twins has not yet been demonstrated, there are individual cases where cf-DNA analysis could be helpful in explaining unusual clinical or laboratory observations. We conclude that cf-DNA analysis and ultrasound have synergistic roles in the management of multiple gestational pregnancies. Key PointsWhat's already known about this topic? � In singleton pregnancies, non-invasive prenatal testing (NIPT) for fetal aneuploidy is more effective than conventional serum and ultrasound-based screening tests.� NIPT is more complex in dizygotic twin pregnancies due to the presence of two fetal genotypes.� Overall fetal fraction is higher in twin pregnancies but the individual contribution for each fetus is lower. What does this study add?� A review of cell-free DNA testing in twin pregnancies.� Individual fetal fractions in dizygotic twin pregnancies can be measured.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Cost of providing cell-free DNA screening for Down syndrome in Finland using different strategies

Cuckle

Heinonen

Anttonen

et al. 2021

Journal of Perinatal Medicine

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Introduction A financial analysis is carried out to assess costs and benefits of providing cell-free DNA screening in Finland, using different strategies. Materials and methods Three cell-free DNA screening strategies are considered: Primary, all women; Secondary, those with positive Combined test; and Contingent, the 10–30% with the highest Combined test risks. Three costs are estimated: additional cost for 10,000 pregnancies compared with the Combined test; ‘marginal’ cost of avoiding a Down syndrome birth which occurs in a pregnancy that would have been false-negative using the Combined test; and marginal cost of preventing the iatrogenic loss of a non-Down syndrome birth which occurs in a pregnancy that would have been false-positive. Results Primary cell-free DNA will require additional funds of €250,000. The marginal cost per Down syndrome birth avoided is considerably less than the lifetime medical and indirect cost; the marginal cost per unaffected iatrogenic fetal loss prevented is higher than one benefit measure but lower than another. If the ultrasound component of the Combined test is retained, as would be in Finland, the additional funds required rise to €992,000. Secondary cell-free DNA is cost-saving as is a Contingent strategy with 10% selected but whilst when 20–30% costs rise they are much less than for the Primary strategy and are cost-beneficial. Conclusions When considering the place of cell-free DNA screening it is important to make explicit the additional and marginal costs of different screening strategies and the associated benefits. Under most assumptions the balance is favorable for Contingent screening.

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Maternal Serum Screening for Chromosomal Abnormalities and Neural Tube Defects

Cited by 3 publications

References 471 publications

Local validation and calibration of pre‐eclampsia screening algorithms

Local validation and calibration of pre‐eclampsia screening algorithms

Non‐invasive prenatal testing in the management of twin pregnancies

Cost of providing cell-free DNA screening for Down syndrome in Finland using different strategies

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