Maiz 2009.
| Clinical features and settings | Routine screening | |
| Participants | 19,614 participants with complete screening and outcome data UK ‐ multicentre January 2006 ‐ May 2007 Pregnant women Singleton pregnancies Median maternal age 34.5 years (14.1‐50.1 years) 11‐13 weeks' gestation |
|
| Study design | Prospective cohort | |
| Target condition and reference standard(s) | Down's syndrome: 122 cases Reference standards: karyotyping or follow‐up to birth |
|
| Index and comparator tests | Maternal age First trimester NT and fetal heart rate First trimester ductus venous blood flow velocity waveforms (FMF certified sonographers) First trimester PAPP‐A and free ßhCG (Delfia Xpress, PerkinElmer) |
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| Follow‐up | Karyotype results and details on pregnancy outcome were added to the database as soon as they became available. Women without complete outcome data (5.3%) were excluded from the study | |
| Aim of study | To investigate the performance of first trimester screening for aneuploidies by including assessment of ductus venosus flow in the combined test of maternal age, fetal NT thickness, fetal heart rate and serum free ßhCG and PAPP‐A | |
| Notes | ||
| Table of Methodological Quality | ||
| Item | Authors' judgement | Description |
| Representative spectrum? All tests | Yes | Routine screening of typical pregnant population |
| Acceptable reference standard? All tests | Yes | Karyotyping or follow‐up to birth |
| Partial verification avoided? All tests | Yes | All women received a reference standard |
| Differential verification avoided? All tests | No | Choice of reference standard depended on index test results |
| Incorporation avoided? All tests | Yes | Reference standard was independent of the index test |
| Reference standard results blinded? All tests | No | Reference standard interpreted with knowledge of index test results |
| Index test results blinded? All tests | Yes | Index test interpreted without knowledge of reference standard results |
| Relevant clinical information? All tests | Yes | Information available as would be in standard clinical practice |
| Uninterpretable results reported? All tests | No | No details given for test failures/uninterpretable measurements |
| Withdrawals explained? All tests | No | No details of withdrawals given |