Hemsell 1987.

Methods	Design: randomised blinded No. eligible: not stated No. randomised: 237 No. analysed: 212 Drop‐outs/withdrawals: 25 (18 did not have scheduled surgery, 6 had intraoperative antibiotics, 1 needed antibiotics postoperatively for pneumonia) Years of recruitment: 1983 to 1985 Setting: Parkland Memorial Hospital, Dallas, Texas, USA
Participants	Inclusion criteria: women having vaginal hysterectomy Exclusion criteria: antibiotic within previous 3 days, allergy to study drugs Age: 32 to 33 years Type of hysterectomy: vaginal
Interventions	Treatment 1: 1 gram cephazolin (first‐generation cephalosporin) Treatment 2: 2 grams cephazolin *Study also compares cephalosporins against each other ‐ data not included Route: IM Single/multiple doses: single Timing of doses: immediately before going to operating theatre
Outcomes	Postoperative infection, late and early + late Pelvic infection Postoperative fever Adverse effects (narrative data only) Need for therapeutic antibiotics Hospital length of stay Cost of surgery (data relate only to direct healthcare costs, minus study drugs ‐ data not included in this review)
Funding	Eli Lilly and Company
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated
Allocation concealment (selection bias)	Low risk	Reported that "vials completely wrapped with paper to obscure identification"
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Probably double‐blinded but no additional details reported on outcome assessor
Incomplete outcome data (attrition bias) All outcomes	Low risk	Proportions of withdrawals and reasons for withdrawals balanced across groups
Selective reporting (reporting bias)	Unclear risk	Insufficient information to make a conclusive judgement
Other bias	Low risk	Baseline demographic characteristics similar between treatment groups