Combined ultrasound and biochemical screening for Down's Syndrome in the first trimester: a Scottish multicentre study

Crossley, Jennifer A.; Aitken, David A.; Cameron, Alan; McBride, Elizabeth C.; Connor, J. M.

doi:10.1111/j.1471-0528.2002.01394.x

Cited by 109 publications

(39 citation statements)

References 32 publications

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“…These rates were similar to those found in previous studies [5,6] . The frequency of fetal Turner's syndrome, 1/1,613 was lower compared to previous studies [3] .…”

Section: Discussionsupporting

confidence: 81%

First Trimester Down’s Syndrome Screening Shows High Detection Rate for Trisomy 21, but Poor Performance in Structural Abnormalities – Regional Outcome Results

Rissanen

Niemimaa

Suonpää³

et al. 2006

Fetal Diagn Ther

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Objective: To evaluate whether first trimester screening markers are altered in pregnancies affected both by other chromosomal defects than trisomy 21 and structural anomalies and whether it is possible to detect these pregnancies by combined ultrasound and biochemical screening test. Methods: Altogether 4,776 singleton pregnancies underwent first trimester screening. Of them, 3,101 women were screened using a combination of maternal serum free hCG, pregnancy-associated plasma protein A and nuchal translucency and 1,361 women with first trimester biochemistry without ultrasound. Nuchal translucency screening was performed between the 11th and 13+6th gestational weeks, and biochemistry 1–2 weeks earlier. Results: Using a fixed cut-off rate of 1:250 for Down’s syndrome, the detection rate of trisomies 21, 18 and 13 were 92, 67 and 0%, respectively. All open defects, 85% of cardiac defects and other minor defects were not detected in first trimester screening. Majority of these structural abnormalities occurred in women under 35 years of age. Conclusion: First trimester Down’s syndrome screening is effective in trisomy screening, but its performance in structural abnormalities is low, when used as a part of routine clinical practice. We conclude that it is too early to drop second trimester screening ultrasound entirely from antenatal care programs if a high detection rate is to be achieved also in structural defects.

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“…These rates were similar to those found in previous studies [5,6] . The frequency of fetal Turner's syndrome, 1/1,613 was lower compared to previous studies [3] .…”

Section: Discussionsupporting

confidence: 81%

First Trimester Down’s Syndrome Screening Shows High Detection Rate for Trisomy 21, but Poor Performance in Structural Abnormalities – Regional Outcome Results

Rissanen

Niemimaa

Suonpää³

et al. 2006

Fetal Diagn Ther

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“…The DR for the contingent screening during the study period was 88.3% for Down syndrome-affected pregnancies with FPR of 3.4%. The DR and FPR are comparable to some reported results from screening programmes (Crossley et al 2002;Rozenberg et al 2007;Okun et al 2008;Wortelboer et al 2009), but performance was nevertheless lower than the published results of large prospective studies (Spencer and Nicolaides 2003;Nicolaides et al 2005). The lower performance rate may by due to a small study group where every case played a major role on DR calculation, and also median maternal age in our study group was 3 years younger than in the large studies.…”

Section: Discussionsupporting

confidence: 77%

Prospective experience with contingent screening strategy for Down syndrome in Estonia

et al. 2010

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The purpose of this study was to establish the first-trimester screening for Down syndrome (DS) in Estonia and to evaluate the potential of a contingent screening in the population of pregnant women. A prospective cohort study included non-selected pregnancies during the programme of first-trimester screening for DS in a 4-year period at a single centre. The following screening tests were evaluated: measurement of nuchal translucency (NT) and serum screening [pregnancy-associated plasma protein A and free beta subunit of human chorionic gonadotropin (fβ-HCG)]; results were given as combined screening. After first-trimester screening, contingent screening protocol was used, and women were divided into three groups: high risk, low risk and an intermediate risk group. In the last group, a second-trimester triple test (AFP; total HCG and uE3) was also performed. The study group consisted of 3,194 non-selected pregnancies. In 1,387 (43.4%) women, first-trimester serum screening showed low risk (risk ≤ 1:5,000), and no future testing was performed, in 30 (0.9%) women screening test showed high risk (risk≥1:50) and a diagnostic test was offered, and in 1,777 (55.7%) women repeated risk calculation in the second trimester was done. During the study period, there were 17 cases of trisomy 21, of which 15 (88.3%) were detected with the described screening programme. In conclusion, two-step contingent sequential screening is a better choice for Down syndrome screening in Estonia instead of previously used second-trimester screening, and it offers the advantage of earlier diagnosis.

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“…This setting differs from most other reports on this topic, in that the NT measurements are being performed as part of routine practice and not as part of a research protocol. 5,6,16,17 Given the widely varying characteristics of our participating laboratories, the findings are likely to be representative of current practice in North America. Overall, 39% of the screened women had NT measured by a sonographer who submitted too few samples to that laboratory for adequate and timely quality assurance monitoring.…”

Section: Discussionmentioning

confidence: 91%

Quality assessment of routine nuchal translucency measurements: a North American laboratory perspective

Palomaki

Neveux

Donnenfeld³

et al. 2008

Genetics in Medicine

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Purpose: To assess nuchal translucency measurements that were performed as part of routine prenatal screening for Down syndrome. Methods: Collect ultrasound measurements of nuchal translucency and crown rump length provided by individual sonographers over a 6-month period to six North American prenatal screening laboratories, along with the laboratory's nuchal translucency interpretation in multiples of the median. For sonographers with 50 or more observations, compute three nuchal translucency quality measures (medians, standard deviations, and slopes), based on epidemiological monitoring. Results: Altogether, 23,462 nuchal translucency measurements were submitted by 850 sonographers. Among the 140 sonographers (16%) who submitted more than 50 observations, 76 (54%) were found to have all three quality measures in the target range. These 140 sonographers collectively accounted for 14,210 nuchal translucency measurements (61%). The most common single measure to be out of range was nuchal translucency multiples of the median, found for 29 of the 140 sonographers (21%). Nuchal translucency (NT) is defined as the collection of fluid behind the fetal neck occurring in the first trimester of pregnancy. 1-3 When measured and interpreted correctly, it is the most discriminatory marker for Down syndrome that has been reported in a routine setting. Univariately, NT measurements can identify about 60% of Down syndrome pregnancies in the first trimester at a 5% false-positive rate. 4 Detection increases to between 80% and 85%, when NT is combined with first trimester biochemical measurements of pregnancyassociated plasma protein-A (PAPP-A) and human chorionic gonadotropin (the intact, total, or free-␤ subunit forms). 4 When NT measurements are incorporated into the integrated test (NT and PAPP-A measurements in the first trimester) and the quadruple test (␣-fetoprotein, unconjugated estriol, human chorionic gonadotropin and dimeric inhibin-A in the second trimester), 85-90% detection is achievable at a false-positive rate of 2% or less. 5,6 Acquiring the skill to properly measure NT requires specialized training and oversight. 7 Recognizing this, several national and international programs have been established to train and qualify sonographers, and also to assess their ability to consistently and accurately quantify the NT thickness. 8 -11 The hands-on performance training is usually evaluated through still images submitted to one, or a panel of, expert sonographers. Several research trials using NT measurements have shown that such training, although necessary, is not sufficient to assure reproducibility of absolute measurements among sonographers. For example, both the Serum, Urine and Ultrasound Screening Study (SURUSS) 5 and First and Second Trimester Evaluation of Risk (FASTER) study 12 found that use of sonographer-specific reference data (medians) resulted in improved screening performance.In the current study, information was sought from screening laboratories regarding how they deal with NT measurements

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Combined ultrasound and biochemical screening for Down's Syndrome in the first trimester: a Scottish multicentre study

Cited by 109 publications

References 32 publications

First Trimester Down’s Syndrome Screening Shows High Detection Rate for Trisomy 21, but Poor Performance in Structural Abnormalities – Regional Outcome Results

First Trimester Down’s Syndrome Screening Shows High Detection Rate for Trisomy 21, but Poor Performance in Structural Abnormalities – Regional Outcome Results

Prospective experience with contingent screening strategy for Down syndrome in Estonia

Quality assessment of routine nuchal translucency measurements: a North American laboratory perspective

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