Jaques 2007.

Clinical features and settings	Routine screening
Participants	16,153 participants Australia ‐ State screening programme February 2000 ‐ June 2002 Pregnant women Mean maternal age 33 years (range 16‐51 years), 18.5% ≥ 37 years 10‐13 weeks' gestation
Study design	Retrospective cohort
Target condition and reference standard(s)	Down's syndrome: 63 cases   Reference standards: karyotyping or follow‐up to birth
Index and comparator tests	Maternal age First trimester NT (FMF accredited ultrasonologists) First trimester PAPP‐A and free ßhCG (details not reported) First trimester AFP, inhibin A and uE3 added to first trimester results for women who were screened at 13 weeks' gestation (augmented screening, number not reported)
Follow‐up	Probabilistic record linkage was used to link health records from the Genetic Health prenatal screening database, Perinatal Data Collection Unit and the Birth Defects Register. Written requests for pregnancy outcome were sent to referring health professionals. Pathology and cytogenetics reports were collected for confirmation of birth defects and/or karyotype 151 women were lost to follow‐up and these were excluded in the analysis Of the 16,003 women, pregnancy loss in 71 due to miscarriage (n = 68), stillbirth (n = 1) and neonatal death (n = 2)
Aim of study	To follow up and evaluate the state‐wide first trimester combined screening programme for Down's syndrome and trisomy 18 at Genetic Health Services Victoria, Australia
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