Thomsen 1987.

Methods	Randomised, placebo‐controlled trial; 2 parallel groups
Participants	Inclusion: positive midstream urine culture for group B streptococcus at 27 to 31 weeks' gestation Setting: University Hospital, Denmark Number of participants: N = 69
Interventions	Penicillin 10 million IU 3 times a day x 6 days, retreated if repeat cultures positive (N = 37) or placebo tablets (N = 32)
Outcomes	Preterm birth (< 37 weeks' gestation) Mean gestational age (39.6 weeks in treatment group (N = 37) vs 36.2 weeks in placebo group (N = 32))
Notes	All mothers positive for group B streptococcus at delivery and their babies were treated with antibiotics Dates of study: October 1984 to October 1986 Funding sources: Leo Pharmaceutical Products (tablets); Nunc, Denmark (equipment) Declarations of interest: none reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as "randomly allocated" but no description of sequence generation process
Allocation concealment (selection bias)	Unclear risk	Method of concealment of allocation not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Placebo‐controlled, described as "double‐blind" but no additional details provided
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Described as "double blinded" but no specific information provided to ensure 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 provided
Other bias	Low risk	The study appears to be free of other sources of bias.
Overall Risk of Bias	Unclear risk	Overall unclear