Kincaid‐Smith 1965.

Methods	Randomised, 'double‐blind' placebo‐controlled; 2 parallel groups
Participants	Inclusion criteria: bacteriuria (> 100,000 bacteria/mL x 2, mid‐stream urine) at first antenatal visit (< 26 weeks). Women with bacteriuria on the first sample that was not confirmed on the second sample were enrolled and results analysed separately. Setting: Melbourne, Australia Number of participants: N = 145
Interventions	Sulphamethoxydiazine 500 mg daily or sulphadimidine 1 g, 3 times a day (after 30 weeks) (N = 61)) vs placebo (N = 55) Treatment continued until delivery Ampicillin or nitrofurantoin given if organism known to be resistant
Outcomes	Pyelonephritis (loin pain or tenderness, with or without pyrexia and rigours, with or without dysuria and frequency) Preterm birth (birthweight < 2500 g) Fetal loss: after 28 weeks 4/61 (6.6%) in treatment group and 4/56 (7.2%) in placebo group Bacteriuria long term: (6 weeks to 3 months after delivery (N = 101) 9/51 treatment vs 18/50 placebo; 6 months after delivery (N = 43) 6/26 treatment vs 6/17 placebo
Notes	29/145 women randomised to treatment but bacteriuria not confirmed on second culture; not included in outcomes reported for this analysis Results for incidence of pyelonephritis and prematurity also provided for women who had bacteriuria at first visit, which was not confirmed on second sample (11/72 in treatment group, 18/73 in placebo group) Dates of study: 1964 to 1965 Funding sources: Felton Bequest Committee; Schering A.G. (Berlin), also provided antibiotic tablets and matching placebo; Beecham Research Laboratories (antibiotic capsules and matching placebo); National Heatlh and Medical Research Council of Australia Declarations of interest: none reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No description of sequence generation process.
Allocation concealment (selection bias)	Low risk	"a code of instructions to the pharmacist ensured that the trial remained double‐blind despite .... alterations in therapeutic regimen."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"a code of instructions to the pharmacist ensured that the trial remained double‐blind despite .... alterations in therapeutic regimen."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"a code of instructions to the pharmacist ensured that the trial remained double‐blind despite .... alterations in therapeutic regimen."
Incomplete outcome data (attrition bias) All outcomes	High risk	240 women initially identified as bacteriuric; no information available on 55 women randomised to treatment (treatment allocation not provided) but not included in the analysis because of poor compliance (attended infrequently or failed to take tablets continuously). For outcome of long‐term persistence of bacteriuria (at 6 months), only 43 women were available for follow‐up.
Selective reporting (reporting bias)	Unclear risk	Insufficient information provided to judge
Other bias	Low risk	The study appears to be free of other sources of bias.
Overall Risk of Bias	Unclear risk	Overall unclear