Koppel 1992.

Methods	RCT. Individual women. 2‐arm study.
Participants	Inclusion criteria Women having a CS. N = 119. Exclusion criteria Women were excluded if they were allergic to penicillin or cephalosporin, or if they had been given a pre‐operative antibiotic treatment within 2 weeks prior to CS.
Interventions	Intervention: cephalosporin (B3). Cefotaxime. 1 g IV with 20 mL NaCl. N = 59. Comparison: penicillin (A4) combination. Amoxicillin plus clavulanic acid. 1.2 g IV with 20 mL NaCl. N = 60.
Outcomes	Endometritis (temperature > 37.5 ºC, uterine tenderness); UTI; wound infection.
Notes	Dates: 17 October 1987 to 24 February 1989. Setting: Kantonspital Hospital, Winterthur, Switzerland. Translation: from German. Subgroups Type of CS not defined. After cord clamping. IV administration. Single dose. Comparisons: 1 (subgroup 2): 2; 3; 4; 10. No information about funding source of study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The translation reports: "A midwife not involved in the study pulled the names from a randomised list and provided the medications in neutral syringes in the operating room." It is unclear if a 'randomised list', is the same as a 'random table' and until we are able to check this we are reporting this as unclear.
Allocation concealment (selection bias)	Unclear risk	A midwife who was not part of the study divided the women into 2 treatment groups, cefotaxim and amoxicillin/clavulanic acid, according to a randomised list.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind trial.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐blind trial.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up.
Selective reporting (reporting bias)	Unclear risk	We did not assess trial protocol.
Other bias	Unclear risk	Baseline characteristics similar for age. However, other possible biases unclear. No information about funding source of study.