Klebanoff 1995.

Methods	Design: randomised, placebo‐controlled, parallel‐group trial
Participants	Number assigned: 938 women (macrolide n = 469, placebo n = 469) Age in years: N/A Setting: secondary care
Interventions	Indication: pregnant women colonised with group B streptococci Type of macrolide: erythromycin base Route: per oral Dose per day: 999 mg Duration of treatment: 10 weeks or until the end of the 35th week of pregnancy, whichever came first Total treatment dose: 69,930 mg (maximum)
Outcomes	Adverse events stated as an outcome in trial registration/protocol/paper: unclear Adverse events ascertainment: spontaneously Adverse events: data reported Antimicrobial resistance: not reported Death: report on death in babies of mothers treated
Funding sources	Study supported by the National Institutes of Health. Authors acknowledge supplying company (The Upjohn Company).
Notes	Concomitant medication: yes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation
Allocation concealment (selection bias)	Low risk	Central allocation
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Identical‐appearing placebo
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Pregnant women and clinicians blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Less than 1% of women not included in reporting of adverse events.
Selective reporting (reporting bias)	Unclear risk	Adverse events not stated clearly as an outcome. Standardised ascertainment. However, adverse events not presented clearly.
Other bias	Low risk	None were identified.