Wren 1969.

Methods	2 parallel groups. Quasi‐RCT
Participants	Inclusion: bacteriuria (midstream urine) x 2 at initial antenatal visits; microbiological criteria not stated Setting: University Hospital, New South Wales, Australia Number of participants: N = 183
Interventions	Nitrofurantoin 100 mg twice a day x 2 weeks, then ampicillin 250 mg every 6 hours x 1 week, then sulphurazole 500 mg every 6 hours x 4 weeks, then nalidixic acid 500 mg every 6 hours x 2 weeks; repeat until 1 to 6 weeks after delivery (N = 83), or no treatment (N = 90)
Outcomes	Preterm birth (< 37 weeks) or low birthweight (< 2500 g)
Notes	There were no stillbirths or neonatal deaths in the treated group; 6 in the no treatment group Dates of study: November 1965 to December 1968 Funding sources: Smith Kline and French Laboratories, Beecham Laboratoies, Roche Products, Winthrop Laboratories Declarations of interest: none reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Women "were divided into two groups, alternate patients being treated".
Allocation concealment (selection bias)	High risk	Women "were divided into two groups, alternate patients being treated".
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding; knowledge of treatment group may have influenced outcome; women in untreated group who developed clinical urinary tract infection (33/90) were given antibiotics at the choice of the obstetrician, continued to delivery in over 50% of cases.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No blinding; however, outcome of birthweight unlikely to be influenced by lack of blinding.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	10 women not included in outcomes: 2 sets of twins excluded, 6 women moved and only 2 could be traced, 3 women delivered before antibiotics could be started, 1 woman refused treatment
Selective reporting (reporting bias)	High risk	Outcome of pyelonephritis not reported
Other bias	Low risk	The study appears to be free of other sources of bias.
Overall Risk of Bias	High risk	Judged as high risk of bias

Please attend closely to the study period for patient enrolment (found under 'Method'); in several instances there were significant delays between the enrolment period and the published report.

ASB: asymptomatic bacteriuria
 BP: blood pressure
 CFU: colony forming units
 G6PD: glucose‐6‐phosphate‐dehydrogenase
 IU: international unit
 RCT: randomised controlled trial
 SD: standard deviation
 SE standard error
 vs: versus