Chantharojwong 1993.

Methods	RCT. Individual women. 2‐arm study.
Participants	Inclusion criteria Women undergoing CS. All considered at risk of infection. Rupture of membranes > 6 hours; labour > 12 hours; cervical effacement and dilatation > 4 cm; > 4 vaginal examinations. N = 109. Exclusion criteria History of allergies to penicillin or cephalosporin; not co‐operative; oral temperature > 38 ºC within period 24 hours prior to operation; received antibiotics within 7 days prior to CS.
Interventions	Intervention: cephalosporin (B1). Cefazolin. 3 g total; 1 g every 6 hours up to 3 doses; IV; just after cord clamping. N = 53 randomised. 1 woman could not be evaluated because she was febrile in the labour room and so was excluded, leaving N = 52. Comparison: penicillin (A4). Ampicillin. 3 g total; 1 g every 6 hours up to 3 doses; IV; just after cord clamping. N = 56 randomised ‐ 2 women could not be evaluated because they were febrile in the labour room and so were excluded, leaving N = 54.
Outcomes	Febrile morbidity; endometritis; parametritis; UTI; wound infection.
Notes	Dates: 1st January 1990 to 31 December 1992. Setting: Inburi Hospital, Thailand. Subgroups Type of CS not defined. After cord clamping. IV administration. Multiple doses. Comparisons: 1(subgroup 1);2; 3; 4. No information about funding source of study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	“... assigned randomly...”
Allocation concealment (selection bias)	Unclear risk	“... assigned randomly...”
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No information provided.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information provided.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only 3 women excluded.
Selective reporting (reporting bias)	Unclear risk	We did not assess the trial protocol.
Other bias	Unclear risk	Baseline characteristics similar between groups on: age; height; weight; gravidity; gestation; preoperative haematocrit. However, other aspects of bias unclear. No information about funding source of study.