Schwarzler 1999.
| Clinical features and settings | Routine screening | |
| Participants | 4523 participants UK ‐ single institution July 1996 to November 1997 Pregnant women Mean age 29.4 years (16‐47 years) 10‐14 weeks' gestation |
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| Study design | Prospective consecutive cohort | |
| Target condition and reference standard(s) | Down's syndrome: 12 cases Reference standards: invasive testing (women considered high risk on screening) or follow‐up to birth |
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| Index and comparator tests | Maternal age NT (Sagittal plane by transabdominal (92.7%) and transvaginal (7.3%) sonography) Adjusted risk cut‐point 1:270 |
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| Follow‐up | Pregnancy outcome obtained via questionnaires, examination by neonatologist and outcome cross‐referenced with regional cytogenetics registry. 26 test‐negative patients lost to follow‐up and excluded from the study | |
| Aim of study | To evaluate first trimester pregnancy screening for fetal aneuploidy and congenital heart defects by maternal age and NT measurement in an unselected population | |
| Notes | 3 live births, 9 termination of pregnancy | |
| 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 |