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Alldred SK, Takwoingi Y, Guo B, Pennant M, Deeks JJ, Neilson JP, Alfirevic Z. First trimester ultrasound tests alone or in combination with first trimester serum tests for Down's syndrome screening. Cochrane Database Syst Rev 2017; 3:CD012600. [PMID: 28295158 PMCID: PMC6464518 DOI: 10.1002/14651858.cd012600] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have. OBJECTIVES To estimate and compare the accuracy of first trimester ultrasound markers alone, and in combination with first trimester serum tests for the detection of Down's syndrome. SEARCH METHODS We carried out extensive literature searches including MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), and The Database of Abstracts of Reviews of Effects (the Cochrane Library 2011, Issue 7). We checked reference lists and published review articles for additional potentially relevant studies. SELECTION CRITERIA Studies evaluating tests of first trimester ultrasound screening, alone or in combination with first trimester serum tests (up to 14 weeks' gestation) for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection. DATA COLLECTION AND ANALYSIS Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses. MAIN RESULTS We included 126 studies (152 publications) involving 1,604,040 fetuses (including 8454 Down's syndrome cases). Studies were generally good quality, although differential verification was common with invasive testing of only high-risk pregnancies. Sixty test combinations were evaluated formed from combinations of 11 different ultrasound markers (nuchal translucency (NT), nasal bone, ductus venosus Doppler, maxillary bone length, fetal heart rate, aberrant right subclavian artery, frontomaxillary facial angle, presence of mitral gap, tricuspid regurgitation, tricuspid blood flow and iliac angle 90 degrees); 12 serum tests (inhibin A, alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (ßhCG), total hCG, pregnancy-associated plasma protein A (PAPP-A), unconjugated oestriol (uE3), disintegrin and metalloprotease 12 (ADAM 12), placental growth factor (PlGF), placental growth hormone (PGH), invasive trophoblast antigen (ITA) (synonymous with hyperglycosylated hCG), growth hormone binding protein (GHBP) and placental protein 13 (PP13)); and maternal age. The most frequently evaluated serum markers in combination with ultrasound markers were PAPP-A and free ßhCG.Comparisons of the 10 most frequently evaluated test strategies showed that a combined NT, PAPP-A, free ßhCG and maternal age test strategy significantly outperformed ultrasound markers alone (with or without maternal age) except nasal bone, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). In both direct and indirect comparisons, the combined NT, PAPP-A, free ßhCG and maternal age test strategy showed superior diagnostic accuracy to an NT and maternal age test strategy (P < 0.0001). Based on the indirect comparison of all available studies for the two tests, the sensitivity (95% confidence interval) estimated at a 5% FPR for the combined NT, PAPP-A, free ßhCG and maternal age test strategy (69 studies; 1,173,853 fetuses including 6010 with Down's syndrome) was 87% (86 to 89) and for the NT and maternal age test strategy (50 studies; 530,874 fetuses including 2701 Down's syndrome pregnancies) was 71% (66 to 75). Combinations of NT with other ultrasound markers, PAPP-A and free ßhCG were evaluated in one or two studies and showed sensitivities of more than 90% and specificities of more than 95%.High-risk populations (defined before screening was done, mainly due to advanced maternal age of 35 years or more, or previous pregnancies affected with Down's syndrome) showed lower detection rates compared to routine screening populations at a 5% FPR. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under-ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting test sensitivity. Conversely, for the NT, PAPP-A, free ßhCG and maternal age test strategy, detection rates and false positive rates increased with maternal age in the five studies that provided data separately for the subset of women aged 35 years or more. AUTHORS' CONCLUSIONS Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.
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Affiliation(s)
- S Kate Alldred
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
| | - Yemisi Takwoingi
- University of BirminghamInstitute of Applied Health ResearchEdgbastonBirminghamUKB15 2TT
| | - Boliang Guo
- University of NottinghamSchool of MedicineCLAHRC, C floor, IHM, Jubilee CampusUniversity of Nottingham, Triumph RoadNottinghamEast MidlandsUKNG7 2TU
| | - Mary Pennant
- Cambridgeshire County CouncilPublic Health DirectorateCambridgeUK
| | - Jonathan J Deeks
- University of BirminghamInstitute of Applied Health ResearchEdgbastonBirminghamUKB15 2TT
| | | | - Zarko Alfirevic
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
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Alldred SK, Takwoingi Y, Guo B, Pennant M, Deeks JJ, Neilson JP, Alfirevic Z. First and second trimester serum tests with and without first trimester ultrasound tests for Down's syndrome screening. Cochrane Database Syst Rev 2017; 3:CD012599. [PMID: 28295159 PMCID: PMC6464364 DOI: 10.1002/14651858.cd012599] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Down's syndrome occurs when a person has three copies of chromosome 21 (or the specific area of chromosome 21 implicated in causing Down's syndrome) rather than two. It is the commonest congenital cause of mental disability. Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing. Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal) and false negative screening tests (i.e. a fetus with Down's syndrome will be missed). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have. OBJECTIVES To estimate and compare the accuracy of first and second trimester serum markers with and without first trimester ultrasound markers for the detection of Down's syndrome in the antenatal period, as combinations of markers. SEARCH METHODS We conducted a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), the Database of Abstracts of Reviews of Effectiveness (the Cochrane Library 25 August 2011), MEDION (25 August 2011), the Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), the National Research Register (Archived 2007), and Health Services Research Projects in Progress database (25 August 2011). We did not apply a diagnostic test search filter. We did forward citation searching in ISI citation indices, Google Scholar and PubMed 'related articles'. We also searched reference lists of retrieved articles SELECTION CRITERIA: Studies evaluating tests of combining first and second trimester maternal serum markers in women up to 24 weeks of gestation for Down's syndrome, with or without first trimester ultrasound markers, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection. DATA COLLECTION AND ANALYSIS Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses. MAIN RESULTS Twenty-two studies (reported in 25 publications) involving 228,615 pregnancies (including 1067 with Down's syndrome) were included. Studies were generally high quality, although differential verification was common with invasive testing of only high risk pregnancies. Ten studies made direct comparisons between tests. Thirty-two different test combinations were evaluated formed from combinations of eight different tests and maternal age; first trimester nuchal translucency (NT) and the serum markers AFP, uE3, total hCG, free βhCG, Inhibin A, PAPP-A and ADAM 12. We looked at tests combining first and second trimester markers with or without ultrasound as complete tests, and we also examined stepwise and contingent strategies.Meta-analysis of the six most frequently evaluated test combinations showed that a test strategy involving maternal age and a combination of first trimester NT and PAPP-A, and second trimester total hCG, uE3, AFP and Inhibin A significantly outperformed other test combinations that involved only one serum marker or NT in the first trimester, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate. However, the evidence was limited in terms of the number of studies evaluating this strategy, and we therefore cannot recommend one single screening strategy. AUTHORS' CONCLUSIONS Tests involving first trimester ultrasound with first and second trimester serum markers in combination with maternal age are significantly better than those without ultrasound, or those evaluating first trimester ultrasound in combination with second trimester serum markers, without first trimester serum markers. We cannot make recommendations about a specific strategy on the basis of the small number of studies available.
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Affiliation(s)
- S Kate Alldred
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
| | - Yemisi Takwoingi
- University of BirminghamInstitute of Applied Health ResearchEdgbastonBirminghamUKB15 2TT
| | - Boliang Guo
- University of NottinghamSchool of MedicineCLAHRC, C floor, IHM, Jubilee CampusUniversity of Nottingham, Triumph RoadNottinghamEast MidlandsUKNG7 2TU
| | - Mary Pennant
- Cambridgeshire County CouncilPublic Health DirectorateCambridgeUK
| | - Jonathan J Deeks
- University of BirminghamInstitute of Applied Health ResearchEdgbastonBirminghamUKB15 2TT
| | | | - Zarko Alfirevic
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
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Alldred SK, Guo B, Takwoingi Y, Pennant M, Wisniewski S, Deeks JJ, Neilson JP, Alfirevic Z. Urine tests for Down's syndrome screening. Cochrane Database Syst Rev 2015; 2015:CD011984. [PMID: 26662198 PMCID: PMC7081127 DOI: 10.1002/14651858.cd011984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Down's syndrome occurs when a person has three copies of chromosome 21, or the specific area of chromosome 21 implicated in causing Down's syndrome, rather than two. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life. The risk of a Down's syndrome affected pregnancy increases with advancing maternal age.Noninvasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing. Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have. OBJECTIVES To estimate and compare the accuracy of first and second trimester urine markers for the detection of Down's syndrome. SEARCH METHODS We carried out a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), EMBASE (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), The Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 2011, Issue 7), MEDION (25 August 2011), The Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), The National Research Register (archived 2007), Health Services Research Projects in Progress database (25 August 2011). We studied reference lists and published review articles. SELECTION CRITERIA Studies evaluating tests of maternal urine in women up to 24 weeks of gestation for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection. DATA COLLECTION AND ANALYSIS We extracted data as test positive or test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS (Quality Assessment of Diagnostic Accuracy Studies) criteria. We used hierarchical summary ROC (receiver operating characteristic) meta-analytical methods to analyse test performance and compare test accuracy. We performed analysis of studies allowing direct comparison between tests. We investigated the impact of maternal age on test performance in subgroup analyses. MAIN RESULTS We included 19 studies involving 18,013 pregnancies (including 527 with Down's syndrome). Studies were generally of high quality, although differential verification was common with invasive testing of only high-risk pregnancies. Twenty-four test combinations were evaluated formed from combinations of the following seven different markers with and without maternal age: AFP (alpha-fetoprotein), ITA (invasive trophoblast antigen), ß-core fragment, free ßhCG (beta human chorionic gonadotrophin), total hCG, oestriol, gonadotropin peptide and various marker ratios. The strategies evaluated included three double tests and seven single tests in combination with maternal age, and one triple test, two double tests and 11 single tests without maternal age. Twelve of the 19 studies only evaluated the performance of a single test strategy while the remaining seven evaluated at least two test strategies. Two marker combinations were evaluated in more than four studies; second trimester ß-core fragment (six studies), and second trimester ß-core fragment with maternal age (five studies).In direct test comparisons, for a 5% false positive rate (FPR), the diagnostic accuracy of the double marker second trimester ß-core fragment and oestriol with maternal age test combination was significantly better (ratio of diagnostic odds ratio (RDOR): 2.2 (95% confidence interval (CI) 1.1 to 4.5), P = 0.02) (summary sensitivity of 73% (CI 57 to 85) at a cut-point of 5% FPR) than that of the single marker test strategy of second trimester ß-core fragment and maternal age (summary sensitivity of 56% (CI 45 to 66) at a cut-point of 5% FPR), but was not significantly better (RDOR: 1.5 (0.8 to 2.8), P = 0.21) than that of the second trimester ß-core fragment to oestriol ratio and maternal age test strategy (summary sensitivity of 71% (CI 51 to 86) at a cut-point of 5% FPR). AUTHORS' CONCLUSIONS Tests involving second trimester ß-core fragment and oestriol with maternal age are significantly more sensitive than the single marker second trimester ß-core fragment and maternal age, however, there were few studies. There is a paucity of evidence available to support the use of urine testing for Down's syndrome screening in clinical practice where alternatives are available.
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Affiliation(s)
- S Kate Alldred
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
| | - Boliang Guo
- University of NottinghamSchool of MedicineCLAHRC, C floor, IHM, Jubilee CampusUniversity of Nottingham, Triumph RoadNottinghamEast MidlandsUKNG7 2TU
| | - Yemisi Takwoingi
- University of BirminghamPublic Health, Epidemiology and BiostatisticsEdgbastonBirminghamUKB15 2TT
| | - Mary Pennant
- Cambridgeshire County CouncilPublic Health DirectorateCambridgeUK
| | - Susanna Wisniewski
- Cochrane Dementia and Cognitive Improvement Group, Oxford UniversityOxfordUK
| | - Jonathan J Deeks
- University of BirminghamPublic Health, Epidemiology and BiostatisticsEdgbastonBirminghamUKB15 2TT
| | - James P Neilson
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
| | - Zarko Alfirevic
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
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Alldred SK, Takwoingi Y, Guo B, Pennant M, Deeks JJ, Neilson JP, Alfirevic Z. First trimester serum tests for Down's syndrome screening. Cochrane Database Syst Rev 2015; 2015:CD011975. [PMID: 26617074 PMCID: PMC6465076 DOI: 10.1002/14651858.cd011975] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Noninvasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing. However, no test can predict the severity of problems a person with Down's syndrome will have. OBJECTIVES The aim of this review was to estimate and compare the accuracy of first trimester serum markers for the detection of Down's syndrome in the antenatal period, both as individual markers and as combinations of markers. Accuracy is described by the proportion of fetuses with Down's syndrome detected by screening before birth (sensitivity or detection rate) and the proportion of women with a low risk (normal) screening test result who subsequently had a baby unaffected by Down's syndrome (specificity). SEARCH METHODS We conducted a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), The Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 25 August 2011), MEDION (25 August 2011), The Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), The National Research Register (Archived 2007), Health Services Research Projects in Progress database (25 August 2011). We did forward citation searching ISI citation indices, Google Scholar and PubMed 'related articles'. We did not apply a diagnostic test search filter. We also searched reference lists and published review articles. SELECTION CRITERIA We included studies in which all women from a given population had one or more index test(s) compared to a reference standard (either chromosomal verification or macroscopic postnatal inspection). Both consecutive series and diagnostic case-control study designs were included. Randomised trials where individuals were randomised to different screening strategies and all verified using a reference standard were also eligible for inclusion. Studies in which test strategies were compared head-to-head either in the same women, or between randomised groups were identified for inclusion in separate comparisons of test strategies. We excluded studies if they included less than five Down's syndrome cases, or more than 20% of participants were not followed up. DATA COLLECTION AND ANALYSIS We extracted data as test positive or test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS (Quality Assessment of Diagnostic Accuracy Studies) criteria. We used hierarchical summary ROC meta-analytical methods or random-effects logistic regression methods to analyse test performance and compare test accuracy as appropriate. Analyses of studies allowing direct and indirect comparisons between tests were undertaken. MAIN RESULTS We included 56 studies (reported in 68 publications) involving 204,759 pregnancies (including 2113 with Down's syndrome). Studies were generally of good quality, although differential verification was common with invasive testing of only high-risk pregnancies. We evaluated 78 test combinations formed from combinations of 18 different tests, with or without maternal age; ADAM12 (a disintegrin and metalloprotease), AFP (alpha-fetoprotein), inhibin, PAPP-A (pregnancy-associated plasma protein A, ITA (invasive trophoblast antigen), free βhCG (beta human chorionic gonadotrophin), PlGF (placental growth factor), SP1 (Schwangerschafts protein 1), total hCG, progesterone, uE3 (unconjugated oestriol), GHBP (growth hormone binding protein), PGH (placental growth hormone), hyperglycosylated hCG, ProMBP (proform of eosinophil major basic protein), hPL (human placental lactogen), (free αhCG, and free ßhCG to AFP ratio. Direct comparisons between two or more tests were made in 27 studies.Meta-analysis of the nine best performing or frequently evaluated test combinations showed that a test strategy involving maternal age and a double marker combination of PAPP-A and free ßhCG significantly outperformed the individual markers (with or without maternal age) detecting about seven out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). Limited evidence suggested that marker combinations involving PAPP-A may be more sensitive than those without PAPP-A. AUTHORS' CONCLUSIONS Tests involving two markers in combination with maternal age, specifically PAPP-A, free βhCG and maternal age are significantly better than those involving single markers with and without age. They detect seven out of 10 Down's affected pregnancies for a fixed 5% FPR. The addition of further markers (triple tests) has not been shown to be statistically superior; the studies included are small with limited power to detect a difference.The screening blood tests themselves have no adverse effects for the woman, over and above the risks of a routine blood test. However some women who have a 'high risk' screening test result, and are given amniocentesis or chorionic villus sampling (CVS) have a risk of miscarrying a baby unaffected by Down's. Parents will need to weigh up this risk when deciding whether or not to have an amniocentesis or CVS following a 'high risk' screening test result.
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Affiliation(s)
- S Kate Alldred
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
| | - Yemisi Takwoingi
- University of BirminghamPublic Health, Epidemiology and BiostatisticsEdgbastonBirminghamUKB15 2TT
| | - Boliang Guo
- University of NottinghamSchool of MedicineCLAHRC, C floor, IHM, Jubilee CampusUniversity of Nottingham, Triumph RoadNottinghamEast MidlandsUKNG7 2TU
| | - Mary Pennant
- Cambridgeshire County CouncilPublic Health DirectorateCambridgeUK
| | - Jonathan J Deeks
- University of BirminghamPublic Health, Epidemiology and BiostatisticsEdgbastonBirminghamUKB15 2TT
| | - James P Neilson
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
| | - Zarko Alfirevic
- The University of LiverpoolDepartment of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
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Bromley B, Shipp TD, Lyons J, Groszmann Y, Navathe RS, Benacerraf BR. What is the importance of second-trimester "soft markers" for trisomy 21 after an 11- to 14-week aneuploidy screening scan? JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2014; 33:1747-1752. [PMID: 25253820 DOI: 10.7863/ultra.33.10.1747] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVES The purpose of this study was to evaluate the importance of second-trimester "soft markers" for trisomy 21 after an 11- to 14-week aneuploidy screening scan. METHODS We conducted a retrospective cohort study of consecutive patients referred for measurement of the nuchal translucency (NT) as part of a screening protocol for aneuploidy. Patients who returned for an anatomic survey between 16 and 20 weeks' gestation were evaluated. The sonographic markers and anomalies associated with the detection of trisomy 21 in the second trimester were analyzed. RESULTS There were 42 fetuses (0.4%) with trisomy 21 identified in the study cohort of 9692 patients. Trisomy 21 was suspected at the NT scan in 28 fetuses (67%) and at the second-trimester anatomic survey in 14 (33%). In fetuses first suspected of having trisomy 21 in the second trimester, 9 of 14 had normal anatomic survey results, and 5 of 14 had congenital malformations. All 14 fetuses had soft markers for aneuploidy. A thickened nuchal fold was identified in 5 of 9 fetuses with trisomy 21 and normal anatomic survey results, all of whom had an NT of less than 3.0 mm at the initial screening scan. CONCLUSIONS Second-trimester soft markers, especially a thickened nuchal fold, remain important observations in the detection of trisomy 21 by sonography among fetuses who have had first-trimester sonographic screening for aneuploidy.
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Affiliation(s)
- Bryann Bromley
- Diagnostic Ultrasound Associates, PC, Boston, Massachusetts USA (B.B., T.D.S., Y.G., B.R.B.); Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, Massachusetts USA (B.B., B.R.B.); Departments of Obstetrics and Gynecology (B.B., T.D.S., Y.G., R.S.N., B.R.B.) and Radiology (B.B., T.D.S., B.R.B.), Brigham and Women's Hospital, Boston, Massachusetts USA; Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts USA (J.L.); and Harvard Vanguard Medical Associates, Boston Massachusetts USA (R.S.N.).
| | - Thomas D Shipp
- Diagnostic Ultrasound Associates, PC, Boston, Massachusetts USA (B.B., T.D.S., Y.G., B.R.B.); Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, Massachusetts USA (B.B., B.R.B.); Departments of Obstetrics and Gynecology (B.B., T.D.S., Y.G., R.S.N., B.R.B.) and Radiology (B.B., T.D.S., B.R.B.), Brigham and Women's Hospital, Boston, Massachusetts USA; Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts USA (J.L.); and Harvard Vanguard Medical Associates, Boston Massachusetts USA (R.S.N.)
| | - Jennifer Lyons
- Diagnostic Ultrasound Associates, PC, Boston, Massachusetts USA (B.B., T.D.S., Y.G., B.R.B.); Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, Massachusetts USA (B.B., B.R.B.); Departments of Obstetrics and Gynecology (B.B., T.D.S., Y.G., R.S.N., B.R.B.) and Radiology (B.B., T.D.S., B.R.B.), Brigham and Women's Hospital, Boston, Massachusetts USA; Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts USA (J.L.); and Harvard Vanguard Medical Associates, Boston Massachusetts USA (R.S.N.)
| | - Yvette Groszmann
- Diagnostic Ultrasound Associates, PC, Boston, Massachusetts USA (B.B., T.D.S., Y.G., B.R.B.); Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, Massachusetts USA (B.B., B.R.B.); Departments of Obstetrics and Gynecology (B.B., T.D.S., Y.G., R.S.N., B.R.B.) and Radiology (B.B., T.D.S., B.R.B.), Brigham and Women's Hospital, Boston, Massachusetts USA; Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts USA (J.L.); and Harvard Vanguard Medical Associates, Boston Massachusetts USA (R.S.N.)
| | - Reshama S Navathe
- Diagnostic Ultrasound Associates, PC, Boston, Massachusetts USA (B.B., T.D.S., Y.G., B.R.B.); Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, Massachusetts USA (B.B., B.R.B.); Departments of Obstetrics and Gynecology (B.B., T.D.S., Y.G., R.S.N., B.R.B.) and Radiology (B.B., T.D.S., B.R.B.), Brigham and Women's Hospital, Boston, Massachusetts USA; Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts USA (J.L.); and Harvard Vanguard Medical Associates, Boston Massachusetts USA (R.S.N.)
| | - Beryl R Benacerraf
- Diagnostic Ultrasound Associates, PC, Boston, Massachusetts USA (B.B., T.D.S., Y.G., B.R.B.); Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, Massachusetts USA (B.B., B.R.B.); Departments of Obstetrics and Gynecology (B.B., T.D.S., Y.G., R.S.N., B.R.B.) and Radiology (B.B., T.D.S., B.R.B.), Brigham and Women's Hospital, Boston, Massachusetts USA; Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts USA (J.L.); and Harvard Vanguard Medical Associates, Boston Massachusetts USA (R.S.N.)
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Guanciali-Franchi P, Iezzi I, Soranno A, de Volo CPB, Alfonsi M, Calabrese G, Benn P. Optimal cut-offs for Down syndrome contingent screening in a population of 10,156 pregnant women. Prenat Diagn 2012; 32:1147-50. [PMID: 23007955 DOI: 10.1002/pd.3974] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
STUDY DESIGN A population of 10,156 pregnant women with singleton pregnancies were screened by the integrated test. Risks were retrospectively recalculated for contingent test strategies with first step intermediate risk groups defined by first trimester upper cut-offs of 1 : 10, 1 : 30, 1 : 50, and 1 : 70 and lower cut-offs 1 : 1500, 1 : 1200, 1 : 1100, and 1 : 900. The second trimester high risk group was based on a single cut-off of 1 : 250. RESULTS In the first trimester, the detection rate (DR) ranged from 21% (6/29) to 52% (15/29) as the high risk first trimester cut-off was changed from 1 : 10 to 1 : 70. The corresponding first trimester false positive rate (FPR) increased from 0.2% to 1.4%. In the second trimester, an additional 21/29 (72%) to 12/29 (41%) affected pregnancies could be detected with an additional 1.6% to 2.7% false positives when lower first trimester cut-offs of 1 : 900 to 1 : 1500 were used. The best results were obtained with the upper first trimester cut-off of 1 : 30 and lower first trimester cut-off of 1 : 900, which yielded a rate of women requiring a second trimester test of only 12%, with overall DR and FPR of 93% and 2.8%, respectively. CONCLUSIONS Although the study population was relatively small, the results confirm the advantage of using contingent screening and suggest optimal first trimester cut-offs of 1 : 30 (lower cut-off) and 1 : 900 (upper cut-off).
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Alldred SK, Deeks JJ, Guo B, Neilson JP, Alfirevic Z. Second trimester serum tests for Down's Syndrome screening. Cochrane Database Syst Rev 2012; 2012:CD009925. [PMID: 22696388 PMCID: PMC7086392 DOI: 10.1002/14651858.cd009925] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Down's syndrome occurs when a person has three copies of chromosome 21 - or the specific area of chromosome 21 implicated in causing Down's syndrome - rather than two. It is the commonest congenital cause of mental retardation. Noninvasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing. OBJECTIVES To estimate and compare the accuracy of second trimester serum markers for the detection of Down's syndrome. SEARCH METHODS We carried out a sensitive and comprehensive literature search of MEDLINE (1980 to May 2007), EMBASE (1980 to 18 May 2007), BIOSIS via EDINA (1985 to 18 May 2007), CINAHL via OVID (1982 to 18 May 2007), The Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 2007, Issue 1), MEDION (May 2007), The Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (May 2007), The National Research Register (May 2007), Health Services Research Projects in Progress database (May 2007). We studied reference lists and published review articles. SELECTION CRITERIA Studies evaluating tests of maternal serum in women at 14-24 weeks of gestation for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection. DATA COLLECTION AND ANALYSIS Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses. MAIN RESULTS Fifty-nine studies involving 341,261 pregnancies (including 1,994 with Down's syndrome) were included. Studies were generally high quality, although differential verification was common with invasive testing of only high-risk pregnancies. Seventeen studies made direct comparisons between tests. Fifty-four test combinations were evaluated formed from combinations of 12 different tests and maternal age; alpha-fetoprotein (AFP), unconjugated oestriol (uE3), total human chorionic gonadotrophin (hCG), free beta human chorionic gonadotrophin (βhCG), free alpha human chorionic gonadotrophin (αhCG), Inhibin A, SP2, CA125, troponin, pregnancy-associated plasma protein A (PAPP-A), placental growth factor (PGF) and proform of eosinophil major basic protein (ProMBP).Meta-analysis of 12 best performing or frequently evaluated test combinations showed double and triple tests (involving AFP, uE3, total hCG, free βhCG) significantly outperform individual markers, detecting six to seven out of every 10 Down's syndrome pregnancies at a 5% false positive rate. Tests additionally involving inhibin performed best (eight out of every 10 Down's syndrome pregnancies) but were not shown to be significantly better than standard triple tests in direct comparisons. Significantly lower sensitivity occurred in women over the age of 35 years. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting the accuracy of the sensitivity. AUTHORS' CONCLUSIONS Tests involving two or more markers in combination with maternal age are significantly more sensitive than those involving one marker. The value of combining four or more tests or including inhibin have not been proven to show statistically significant improvement. Further study is required to investigate reduced test performance in women aged over 35 and the impact of differential pregnancy loss on study findings.
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Affiliation(s)
- S Kate Alldred
- Department of Women’s and Children’s Health, The University of Liverpool, Liverpool, UK.
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COCCIOLONE R, BRAMELD K, O’LEARY P, HAAN E, MULLER P, SHAND K. Combining first and second trimester markers for Down syndrome screening: Think twice. Aust N Z J Obstet Gynaecol 2008; 48:492-500. [DOI: 10.1111/j.1479-828x.2008.00911.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Cuckle HS, Malone FD, Wright D, Porter TF, Nyberg DA, Comstock CH, Saade GR, Berkowitz RL, Ferreira JC, Dugoff L, Craigo SD, Timor IE, Carr SR, Wolfe HM, D'Alton ME. Contingent screening for Down syndrome--results from the FaSTER trial. Prenat Diagn 2008; 28:89-94. [PMID: 18236423 DOI: 10.1002/pd.1913] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Comparison of contingent, step-wise and integrated screening policies. METHODS Mid-trimester Down syndrome risks were retrospectively calculated from FaSTER trial data. For contingent screening, initial risk was calculated from ultrasound measurement of nuchal translucency (NT), maternal serum pregnancy-associated plasma protein (PAPP)-A and free beta-human chorionic gonadotrophin (hCG) at 11-13 weeks, and classified positive (>1 in 30), borderline (1 in 30-1500) or negative. Borderline risks were recalculated using alpha-fetoprotein, hCG, unconjugated estriol (uE3) and inhibin at 15-18 weeks, and reclassified as positive (>1 in 270) or negative. For step-wise screening, initial negative risks were also recalculated. For integrated screening, a single risk was calculated from NT, PAPP-A and the second trimester markers. RESULTS There were 86 Down syndrome and 32,269 unaffected pregancies. The detection rate for contingent screening was 91% and false-positive rate was 4.5%; initial detection rate was 60%, initial false-positive rate was 1.2% and borderline risk was 23%. Step-wise screening had 92% detection rate and 5.1% false-positive rate; integrated screening had 88% and 4.9% respectively. CONCLUSION As predicted by modelling, the contingent screening detection rate for a fixed false-positive rate is comparable with step-wise and integrated screening, but substantially reduces the number needing to return for second trimester testing.
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Bibliography. Current world literature. Maternal-fetal medicine. Curr Opin Obstet Gynecol 2007; 19:196-201. [PMID: 17353689 DOI: 10.1097/gco.0b013e32812142e7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Wright D, Bradbury I, Cuckle H, Gardosi J, Tonks A, Standing S, Benn P. Three-stage contingent screening for Down syndrome. Prenat Diagn 2006; 26:528-34. [PMID: 16634118 DOI: 10.1002/pd.1451] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To demonstrate the potential value of three-stage sequential screening for Down syndrome. METHODS Protocols were considered in which maternal serum pregnancy associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (hCG) measurements were taken on all women in the first trimester. Those women with very low Down syndrome risks were screened negative at that stage and nuchal translucency (NT) was measured on the remainder and the risk reassessed. Those with very low risk were then screened negative and those with very high risk were offered early diagnostic testing. Those with intermediate risks received second-trimester maternal serum alpha-fetoprotein, free beta-hCG, unconjugated estriol and inhibin-A. Risk was then reassessed and those with high risk were offered diagnosis. Detection rates and false-positive rates were estimated by multivariate Gaussian modelling using Monte-Carlo simulation. RESULTS The modelling suggests that, with full adherence to a three-stage policy, overall detection rates of nearly 90% and false-positive rates below 2.0% can be achieved. Approximately two-thirds of pregnancies are screened on the basis of first-trimester biochemistry alone, five out of six women complete their screening in the first trimester, and the first-trimester detection rate is over 60%. CONCLUSION Three-stage contingent sequential screening is potentially highly effective for Down syndrome screening. The acceptability of this protocol and its performance in practice, should be tested in prospective studies.
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Affiliation(s)
- Dave Wright
- Department of Mathematics and Statistics, University of Plymouth, UK.
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Cuckle H, Benn P, Wright D. Down syndrome screening in the first and/or second trimester: model predicted performance using meta-analysis parameters. Semin Perinatol 2005; 29:252-7. [PMID: 16104677 DOI: 10.1053/j.semperi.2005.05.004] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To predict the screening performance for 17 policies currently in use or being considered for the near future. METHODS Multivariate Gaussian modeling using parameters derived from published meta-analyses and new meta-analyses for gestation-specific nuchal translucency and between trimester correlations. RESULTS For a 1% to 5% false-positive rate, first trimester screening achieved detection rates up to 16% to 25% higher than the best second trimester combination. Screening in both trimesters sequentially could yield an even greater increase in detection of 24% to 35%. The most efficient sequential policy was contingent screening, which has a high detection rate with only 15% of women needing second trimester tests. CONCLUSION Modeling with meta-analysis derived parameters provides a reliable guide for policy and favors a contingent screening policy. The widespread practice of calculating first and second trimester risks separately should be abandoned.
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