Methods	Sealed envelopes.
Participants	2834 singleton pregnancies. Criteria for recruitment were gestational age 16-20 weeks, sufficient proficiency in English, expected to deliver at the hospital and an intention to remain in Western Australia so that childhood follow up would be feasible
Interventions	The ’regular’ group had an ultrasound examination at 18 weeks for fetal biometry, subjective amniotic fluid assessment and placental morphology and location, and any further scans in pregnancy were conducted on clinicians request. The ’intensive group’ had the aforementioned ultrasound examination, plus an amniotic fluid index and continuous wave Doppler ultrasound of the umbilical artery and an arcuate artery within the placental vascular bed at 18, 24, 28, 34 and 38 weeks’ gestation. The Doppler ultrasound parameter reportedwas systolic/diastolic ratio. Results of these examinations were recorded in the hospital chart, but no clinical management guidance was given
Outcomes	Obstetric interventions (antepartum and intrapartum) and perinatal outcome indices
Notes	The published study reports the results overall, but little data are available for extraction. The authors were contacted and provided unpublished data
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	Described as “computer-generated random numbers”.
Allocation concealment?	Unclear	Described as “sealed envelopes”.
Blinding? Women	No	Not feasible.
Blinding? Clinical staff	No	Not feasible.
Blinding? Outcome assessors	No	Not feasible.
Incomplete outcome data addressed? All outcomes	Unclear	Some loss to follow up in both groups. “13 were lost to follow up in the intensive group of the trial and 20 in the regular” care group
Free of selective reporting?	Yes	Selective outcome reporting bias not detected.
Free of other bias?	Yes	Other bias not detected.