Methods	Pseudorandomisation according to last digit in hospital number
Participants	877 women attending the hospital antenatal clinic between 34-36.5 weeks’ gestation with uncomplicated singleton pregnancies, i.e. low-risk pregnancies
Interventions	All women had an ultrasound examination <; 24 weeks’ gestation for gestational dating. All had further ultrasound scan at 34-36.5 weeks’ gestation to measure crown rump length and trunk area, but in the study group the two measurements were multiplied and the results plotted and reported in the case notes (i.e. revealed). Further management was the responsibility of the clinical staff. No requests for control group measurements to be revealed occurred, but this option was available to clinicians
Outcomes	Obstetric interventions (antepartum and intrapartum) and perinatal outcome indices
Notes	This study addressed ultrasound screening for small for dates
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	No	Described as allocated “from their hospital index numbers”.
Allocation concealment?	No	See above.
Blinding? Women	No	Not feasible.
Blinding? Clinical staff	No	Not feasible.
Blinding? Outcome assessors	No	Not feasible.
Incomplete outcome data addressed? All outcomes	Unclear	Small loss to follow up.
Free of selective reporting?	Yes	Selective outcome reporting not detected.
Free of other bias?	Unclear	There were more participants from social class V in the reported group