Little 1966.

Methods	Placebo‐controlled, randomised; 2 parallel groups
Participants	Inclusion criteria: bacteriuria (> 100,000 bacteria/mL x 2, midstream urine) at first prenatal visit Setting: London, England Number of participants: N = 265
Interventions	Sulphamethoxypyridazine 500 mg or (later) nitrofurantoin 100 mg daily continued until 6 weeks after delivery; ampicillin or nitrofurantoin were alternatives for failures (N = 124) or placebo (N = 141)
Outcomes	Pyelonephritis (loin pain and tenderness, fever and > 100,000 bacteria/mL) Low birthweight (< 2500 g)
Notes	Dates of study: 1962 to 1965 Funding sources: Dan Mason Research Foundation of the West London Medical Trust; Smith Kline and French Laboratories, Eaton Laboratories, Park Davis and Co, Beecham Research Laboratories, Cerebos Ltd and the Ockley Brick Works Declarations of interest: none reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided about sequence generation to permit judgement.
Allocation concealment (selection bias)	Unclear risk	Allocation to treatment or control was drawn from "a pool of sealed envelopes containing a slip of paper", but there was no information provided to ensure appropriate safeguards to prevent investigators being aware of treatment group.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Women in the control group "were given placebo"; no further details provided
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information provided to judge whether outcome assessment was blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Unclear risk	Insufficient information 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