Methods	Randomised controlled trial. Individual women.
Participants	Inclusion criteria Unselected population. Women attending the AN before 26 weeks’ gestation, there was no attempt at selection, so women were eligible for inclusion, regardless of whether they had high-risk features). Exclusion criteria Multiple pregnancies.
Interventions	Experimental intervention: umbilical Doppler US revealed Umbilical artery systolic/diastolic ratio revealed. Doppler US made available from 26 to 30 weeks (1st window) and 34 to 36 weeks (2nd window). N = 1642. Control/Comparison intervention: no Doppler Doppler concealed. N = 1344. Multiple estimations were at 26-30 weeks and 34-36 weeks. Of the 2986 women in the study, 1386 underwent examination at both gestational windows, 1056 at only the first and 544 at only the second
Outcomes	Antenatal complications; antenatal admissions; day care visits; elective delivery; elective CS; CS in labour; CS for FD; birth < 32 weeks; Apgar scores; small for dates; admission to SCBU; ventilations; stillbirth
Notes	Glasgow (UK) 1994 study in previous version of the review (Bricker 2007).
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	“the order was generated by random-number tables.”
Allocation concealment?	Yes	“sealed opaque envelopes” “numbered.”
Incomplete outcome data addressed? All outcomes	Unclear	Describe any loss of participants to follow up at each data collection point: No dropouts (in comment). Describe any exclusion of participants after randomisation: Not specified. Was the analysis ITT? If not has the data been able to be re-included?
Free of selective reporting?	Unclear	We did not assess the trial protocol.
Free of other bias?	No	If the study was stopped early, explain the reasons: Not stopped earlier. Describe any baseline in balance: Numbers of women in each group were not similar - see below. Groups were similar for parity and gestational age. The difference in age was small 27.9 vs 27.2 but it was statistically significant. There were more abnormal Doppler at the first window (26 to 30 weeks) namely 33 for revealed and 148 for concealed but similar numbers at the 2nd window (34-36 weeks) namely 69 for revealed and 66 for concealed. Describe any differential diagnosis: Groups were well matched except for abnormal Doppler at first window. “It is possible that this may have occurred through unintentionally less persistent attempts to obtain a normal waveform in the concealed group than in the revealed group. If this did occur, however, one would have expected to see evidence of the same trend at the second screen, and this was not so.” Also: The numbers in each group were not similar (1642 vs 1344) suggesting a problem with the randomisation. The authors also noticed this and reported “…due to secretarial error in preparation of the envelopes…previously used random numbers had been ‘recycled’ through the study”.

AN: antenatal

BP: blood pressure

CTG: cardiotocography

FD:

ITT: intention to treat

IUGR: intrauterine growth restriction

NICU: neonatal intensive care unit

PIH: pregnancy-induced hypertension

PNM: perinatal mortality

SCBU: special care baby unit

SGA: small-for-gestational age

US: ultrasound

VS: versus