Louie 1982.

Methods	RCT. Individual women. 3‐arm study.
Participants	Inclusion criteria All women undergoing emergency CS. Women in active labour with membrane rupture prior to surgery; rectal temperature < 37.8 ºC ; no history of penicillin or cephalosporin allergy; no antibiotic therapy in previous 2 weeks. N = 195 but data on 188. Exclusion criteria None specified.
Interventions	Intervention 1: cephalosporin (B1). Cefazolin. 1g IV after cord clamped and 2 further doses at 6 and 12 hours post‐operation. N = 70. Intervention 2: cephalosporin (B3). Cefotaxime. 1 g IV after cord clamped and 2 further doses at 6 and 12 hours post‐operation. N = 58. Comparison: penicillin (A4). Ampicillin. 1 g IV after cord clamped and 2 further doses at 6 and 12 hours post‐operation. N = 60. For the purposes of this review we have pooled the data for cefazolin and cefotaxime. Any differences between these 2 cephalosporins will be assessed in the review on 'Different regimens of cephalosporin antibiotic prophylaxis at caesarean section for reducing maternal morbidity'.
Outcomes	Endometritis (temperature > 38 ºC, foul lochia, uterine tenderness); UTI; wound infection; febrile morbidity (temp > 38 ºC x 2, 6 hours apart, excluding first 24 hours).
Notes	Dates: December 1979 to December 1981. Setting: Women's Centre at the Health Sciences Winnipeg, Canada. Subgroups Non‐elective CS. After cord clamping. IV administration. Multiple doses. Comparisons: 1 (subgroup 1); 2; 3; 4; 6; 10. No information about funding source of study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	“...randomised...”.
Allocation concealment (selection bias)	Low risk	“..unlabelled but number‐coded, previously randomised vials...”.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind trial.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	“Only pharmacist was aware of the drug code.”
Incomplete outcome data (attrition bias) All outcomes	Low risk	7/195 (3.6%) lost to follow‐up. Similar across groups.
Selective reporting (reporting bias)	Unclear risk	We did not assess trial protocol.
Other bias	Unclear risk	Baseline characteristics similar for age and race. However, other possible biases were unclear. No information about funding source of study.