Matias 2001.
| Clinical features and settings | High‐risk referral for invasive testing | |
| Participants | 515 participants Portugal Dates not reported Pregnant women Median age 35 years (17‐46 years) Singleton pregnancies 11‐14 weeks' gestation |
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| Study design | Prospective cohort study | |
| Target condition and reference standard(s) | Down's syndrome: 43 cases Reference standards: fetal karyotyping. In cases where NT above 95th percentile, follow‐up scan conducted at 14‐16 weeks |
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| Index and comparator tests | Maternal age First trimester NT (SSD, Aloka) First trimester ductus venous Doppler evaluation ‐ ductus venosus flow velocity ‐ abnormal flow is defined as absent or reversed flow of blood in the ductus venosus, normal flow defined as presence. Measurement made by obtaining the right ventral midsaggital plane of the fetal trunk in fetal quiescence. Pulsed Doppler gate placed in distal portion of umbilical sinus. 5 consecutive high‐quality waveforms used to measure peak velocity during ventricular systole and diastole, the lowest forward velocity during atrial contraction in late diastole and the pulsatility index. Up to 10 minutes allowed for measurements |
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| Follow‐up | All women received karyotyping. Unclear if patients followed up to birth | |
| Aim of study | To review the role of Doppler ultrasound in screening for chromosomal abnormalities at 11 to 14 weeks of gestation | |
| Notes | ||
| Table of Methodological Quality | ||
| Item | Authors' judgement | Description |
| Representative spectrum? All tests | Yes | Selective testing of high‐risk women as done in practice |
| Acceptable reference standard? All tests | Yes | Karyotyping |
| Partial verification avoided? All tests | Yes | All women had a reference standard |
| Differential verification avoided? All tests | Yes | All women had the same reference standard |
| 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 | Yes | Reported that Doppler measurements made successfully in all cases |
| Withdrawals explained? All tests | No | No details of withdrawals given |