Methods	Randomisation by sealed envelopes.
Participants	Nearly all women in that geographical area, including those with ‘high-risk’ pregnancies. Recruitment 1979-1981. 1628 women
Interventions	Routine ultrasound examination at 18 weeks (biparietal diameter measured) and 32 weeks (biparietal diameter and mean abdominal diameter) with additional examination at 36 weeks’ gestation if fetus small-for-gestational age and/or presenting by breech - versus selective examination for clinical indications only
Outcomes	Obstetric interventions (antepartum and intrapartum) for singleton pregnancies only. Perinatal outcome indices for all pregnancies (including multiple pregnancies)
Notes	This trial was reported in letter form only in 1984. It subsequently became clear that there were inconsistencies in results, and the data were subsequently re-analysed. The data entered in this review are derived from more recent unpublished and published reports
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Not stated.
Allocation concealment?	Unclear	Described as “sealed envelope”.
Blinding? Women	No	Not feasible.
Blinding? Clinical staff	No	Not feasible.
Blinding? Outcome assessors	No	Not feasible.
Incomplete outcome data addressed? All outcomes	Yes	The data could be re-included.
Free of selective reporting?	Yes	Selective outcome reporting bias not apparent.
Free of other bias?	No	More smokers in screened group; historical study.