P11.08: Screening tests for chromosomal pathologies in the first trimester: combined test v/s nuchal translucency thickness

Introduction: Contingent cell-free (cf) DNA screening on the basis of the first-trimester combined test (FCT) results has emerged as a cost-effective strategy for screening of trisomy 21 (T21). Objectives: To assess performance, patients’ uptake, and cost of contingent cfDNA screening and to compare them with those of the established FCT. Methods: This is a prospective cohort study including all singleton pregnancies attending to their FCT for screening of T21 at 2 university hospitals in South Spain. When the FCT risk was ≥1:50, there were major fetal malformations, or the nuchal translucency was ≥3.5 mm, women were recommended invasive testing (IT); if the risk was between 1:50 and 1:270, women were recommended cfDNA testing; and for risks bellow 1:270, no further testing was recommended. Detection rate (DR), false-positive rate (FPR), patients’ uptake, and associated costs were evaluated. Results: We analyzed 10,541 women, including 46 T21 cases. DR of our contingent strategy was 89.1% (41/46) at 1.4% (146/10,541) FPR. Uptake of cfDNA testing was 91.2% (340/373), and overall IT rate was 2.0%. The total cost of our strategy was €1,462,895.7, similar to €1,446,525.7 had cfDNA testing not been available. Conclusions: Contingent cfDNA screening shows high DR, low IT rate, and high uptake at a similar cost than traditional screening.

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First-trimester screening for Down syndrome using nuchal translucency measurement with free β-hCG and PAPP-A between 10 and 13 weeks of pregnancy—the combined test

Prenatal Diagnosis ◽

10.1002/(sici)1097-0223(199904)19:4<360::aid-pd556>3.0.co;2-u ◽

1999 ◽

Vol 19 (4) ◽

pp. 360-363 ◽

Cited By ~ 76

Author(s):

P. De Biasio ◽

M. Siccardi ◽

G. Volpe ◽

L. Famularo ◽

F. Santi ◽

...

Keyword(s):

Down Syndrome ◽

First Trimester ◽

Nuchal Translucency ◽

First Trimester Screening ◽

Combined Test ◽

Trimester Screening ◽

Nuchal Translucency Measurement ◽

Β Hcg

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First trimester Down's syndrome screening marker values and cigarette smoking: new data and a meta-analysis on free β human chorionic gonadotophin, pregnancy-associated plasma protein-A and nuchal translucency

Journal of Medical Screening ◽

10.1258/jms.2008.008049 ◽

2008 ◽

Vol 15 (4) ◽

pp. 204-206 ◽

Cited By ~ 16

Author(s):

Jonathan P Bestwick ◽

Wayne J Huttly ◽

Nicholas J Wald

Keyword(s):

Meta Analysis ◽

False Positive Rate ◽

Protein A ◽

First Trimester ◽

Nuchal Translucency ◽

Screening Performance ◽

Combined Test ◽

Positive Rate ◽

Trimester Screening ◽

Β Hcg

Objectives To examine the effect of smoking on three first trimester screening markers for Down's syndrome that constitute the Combined test, namely nuchal translucency (NT), pregnancy-associated plasma protein-A (PAPP-A) and free β human chorionic gonadotophin (free β-hCG) and to use the results to determine which of these markers need to be adjusted for smoking and by how much. Methods The difference in the median multiple of the median (MoM) values in smokers compared to non-smokers was determined for NT, PAPP-A and free β-hCG in 12,517 unaffected pregnancies that had routine first trimester Combined test screening. These results were then included in a meta-analysis of published studies and the effect of adjusting for smoking on screening performance of the Combined test was estimated. Results The results using the routine screening data were similar to the summary estimates from the meta-analysis of all studies. The results from the meta-analysis were; median MoM in smokers compared to non-smokers: 1.06 NT (95% confidence interval 1.03 to 1.10), 0.81 PAPP-A (0.80 to 0.83) and 0.94 free β-hCG (0.89 to 0.99). The effect of adjusting for smoking on the Combined test is small, with an estimated less than half percentage point increase in the detection rate (the proportion of affected pregnancies with a positive result) for a 3% false-positive rate (the proportion of unaffected pregnancies with a positive result) and less than 0.2 percentage point decrease in the false-positive rate for an 85% detection rate. Conclusion Adjusting first trimester screening markers for smoking has a minimal favourable effect on screening performance, but it is simple to implement and this paper provides the adjustment factors needed if a decision is made to make such an adjustment.

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Prenatal Screening for Down Syndrome in Australia

Ultrasound ◽

10.1179/174313409x457921 ◽

2009 ◽

Vol 17 (3) ◽

pp. 167-171

Author(s):

Debbie L Nisbet ◽

Andrew McLennan

Keyword(s):

Down Syndrome ◽

Prenatal Screening ◽

False Positive Rate ◽

First Trimester ◽

Nuchal Translucency ◽

Maternal Serum ◽

Screening Tests ◽

Maternal Serum Screening ◽

Serum Screening ◽

Maternal Preference

Prenatal screening for Down syndrome should be offered to all pregnant women. The screening option chosen will be influenced by maternal preference, local availability of tests, and the gestation at which the pregnant woman presents. Screening tests take into account the effect of maternal age on Down syndrome risk. The combined first trimester screen using nuchal translucency and first trimester maternal serum screening can achieve a detection rate for Down syndrome of 90% with a 5% false positive rate, when performed by appropriately trained individuals. Midtrimester maternal serum screening is a good screening option for women unable to undergo the combined first trimester screen.

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Combined first trimester nuchal translucency and second trimester biochemical screening tests among normal pregnancies

Prenatal Diagnosis ◽

10.1002/1097-0223(200010)20:10<781::aid-pd908>3.0.co;2-z ◽

2000 ◽

Vol 20 (10) ◽

pp. 781-784 ◽

Cited By ~ 13

Author(s):

A. Herman ◽

Z. Weinraub ◽

E. Dreazen ◽

S. Arieli ◽

S. Rozansky ◽

...

Keyword(s):

First Trimester ◽

Nuchal Translucency ◽

Screening Tests ◽

Second Trimester ◽

Biochemical Screening

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Correlation Between Serum Biochemical Markers and Early Amniocentesis in Diagnosis of Congenital Fetal Anomalies

Bosnian Journal of Basic Medical Sciences ◽

10.17305/bjbms.2010.2726 ◽

2010 ◽

Vol 10 (1) ◽

pp. 9-14 ◽

Cited By ~ 2

Author(s):

Dragan Lončar ◽

Mirjana Varjačić ◽

Tanja Novaković ◽

Dragan Milovanović ◽

Slobodan Janković

Keyword(s):

Pregnant Women ◽

Venous Blood ◽

Rank Correlation ◽

First Trimester ◽

Total Sample ◽

Nuchal Translucency ◽

Serum Marker ◽

Great Accuracy ◽

Crown Rump Length ◽

Combined Test

A combined test performed at the 12th week of gestation enables us to classify the pregnancy as high risk (risk higher than 1:300) or low risk (risk lower than 1:300) for congenital foetal anomalies, with great accuracy of 85 - 90%. According to the available data, the frequency of false positive results is estimated at around 5%. The objective of the study was to examine possible correlation between the serum marker values and amniocentesis results in prenatal diagnostics of congenital foetal anomalies. The study included 745 pregnant women monitored by the Genetic Counselling Service of the Clinic of Gynaecology and Obstetrics of the Clinics Centre Kragujevac. The subjects were included in the study under condition that CRL (embryonic crown-rump length) was from 45 to 84 mm and that the gestational age was at 11-13+6 weeks. Free β HCG and PAPP-A were determined from venous blood using commercial DPS-USA tests. Tests were based on the analytic principle of the immuno-chemiluminescence technique and were performed by application of the automatic Immulite 2000 analyzer by DPC-USA. The foetal nuchal translucency thickness (NT) and CRL were measured by Colour Doppler. The chromosome identification was performed after a certain number of cell divisions by stopping the cell division in metaphase of mitosis when the chromosomes were the most distinguishable. The foetal karyotype was prepared using G bands. In the total sample of pregnant women (n=745), there were six cases of pathological foetal karyotype. A statistical paradox in the frequency of congenital foetal anomalies in favour of younger population was noticed. A high coefficient of Spearman’s rank correlation suggests great importance of the combined test in the detection of congenital foetal anomalies (p<0,05). A high consistency was also proved for components of biochemical screening and ultrasonographic markers. The combined test, as a method of prenatal screening in the first trimester of pregnancy, if used at 11 - 13+6 weeks’ gestation and for CRL of 45-84 mm, has a great importance in the detection of congenital foetal anomalies.

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First-Trimester or Second-Trimester Screening, or Both, for Down Syndrome

50 Studies Every Obstetrician-Gynecologist Should Know ◽

10.1093/med/9780190947088.003.0020 ◽

2021 ◽

pp. 108-114

Author(s):

Jessica M. Hart ◽

Barbara M. O’Brien

Keyword(s):

Down Syndrome ◽

First Trimester ◽

Nuchal Translucency ◽

The United States ◽

Screening Tests ◽

Second Trimester ◽

Detection Rates ◽

Fully Integrated ◽

Second Trimester Screening ◽

Trimester Screening

The FASTER Trial by Malone et al. discusses methods of prenatal genetic screening for Down syndrome. The trial included 15 sites within the United States between 1999 and 2005. This trial was designed to compare the differences in detection rates of Down syndrome when applying screening tests from the first-trimester, second-trimester, or screening tests that combine markers from both trimesters. Screening tests evaluated in this trial include nuchal translucency, serum screen, combined screen, quadruple screen, independent sequential screen, stepwise sequential screen, serum integrated screen, and fully integrated screen. This trial compares detection rates, false positive rates, and timing of results between screening tests.

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Nuchal translucency measurement: The effect of 3D/4D ultrasound

Medicinski pregled ◽

10.2298/mpns1304145k ◽

2013 ◽

Vol 66 (3-4) ◽

pp. 145-148

Author(s):

Gordana Kozarov ◽

Tanja Marjanovic-Milosevic ◽

Bosko Vuksic

Keyword(s):

Standard Error ◽

Chromosomal Abnormalities ◽

First Trimester ◽

Nuchal Translucency ◽

Advanced Technology ◽

Screening Tests ◽

Detection Rates ◽

Crown Rump Length ◽

4D Ultrasound ◽

2D Ultrasound

Introduction. Nuchal translucency thickness has undoubtedly been proven as an important marker in screening for chromosomal abnormalities. It is measured in the first trimester by ultrasound. This study was aimed at determining the effect of 3D/4D ultrasound on standard error of mean nuchal translucency measurements. Material and Methods. Having satisfied the inclusion criteria, 430 nuchal translucency measurements were analyzed (singleton pregnancies, 11+0-13+6 weeks of gestation, crown rump length 45-84mm, postnatally confirmed absence of anomalies). The data were divided into two groups, depending on the method used (older generation 2D ultrasound or 3D/4D ultrasound). The reported nuchal translucency measurements were converted into multiple of median values of nuchal translucency and 95% confidence interval was calculated for the two sets of data. Results. The standard error of mean values has decreased from 0.027, when nuchal translucency was mea-sured via 2D ultrasound, to 0.016 when 3D/4D ultrasound was used for the measurements. Discussion. The detection rates of prenatal screening tests can be increased and the false positive rates can be decreased by lowering the standard error of mean value. Conclusion. Advanced technology and developed automated measuring of nuchal translucency should result in further enhancements in early detection of fetal abnormalities.

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