Methods	Randomised controlled trial, individual women.
Participants	Inclusion criteria Primagravida women with a negative medical and gynaecological history and physical examinations were identified at booking clinic. N = 2145 were randomised but 2025 analysed. Exclusion criteria Twin pregnancies.
Interventions	Experimental intervention: umbilical artery Doppler ultrasound Multiple at 28 weeks and again at 34 weeks. N = 1073. Control/comparison intervention: routine care, no Doppler ultrasound Clinician could request Doppler if felt indicated. 3.9% (42 women) were referred for Doppler US. N = 1072. Multiple estimations were at 28 and 34 weeks’ gestation.
Outcomes	Main outcome: obstetric intervention rate, short-term neonatal morbidity
Notes	Leeds (UK) 1993 study in previous version of the review (Bricker 2007).
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	“Tables of random numbers were used to generate each random permuted block.”
Allocation concealment?	Unclear	“…opaque numbered envelopes which were opened on the fetal assessment unit by a radiographer who had no personal knowledge of the women or her history.” No mention if enveloped were sealed.
Incomplete outcome data addressed? All outcomes	Yes	Describe any loss of participants to follow up at each data collection point: 53/1073 (5%) women in Doppler were lost to follow up. 67/1072 (6%) women in No Doppler were lost to follow up. Describe any exclusion of participants after randomisation: 5 sets of twins were excluded from Doppler and 4 from control.
Free of selective reporting?	Unclear	We did not assess the trial protocol.
Free of other bias?	Unclear	If the study was stopped early, explain the reasons: Not stopped early for benefit or harm. Describe any baseline in balance: Balanced according to: age, weight before pregnancy, primapara, educational level, gestational age at inclusion, biparietal diameter, transverse abdominal diameter. 863 (80%) of those offered Doppler attended for assessment. In the control group 42 (3.9%) women were referred for a total of 191 Doppler assessments. The relatively lower compliance at 34 weeks than at 28 weeks was probably related to the hospital policy of a routine visit at 28 weeks but not at 34 weeks. Describe any differential diagnosis: Seems ok.