Stiver 1983.

Methods	Randomized, placebo‐controlled trial; 3 parallel groups. Unit of randomization: individual.
Participants	Dates of data collectin: no reported. Setting: 5 centers in Canada. Inclusion criteria: all women in labor or with ruptured membranes (duration of ruptured membranes not stated; mean duration 9.97 hrs; included in both category). N = 361.
Interventions	Intervention 1: 1st generation cephalosporin: cefazolin 1 g; N = 120. Intervention 2: cefamycin: cefoxitin 2 g; N = 124. Comparison: placebo: placebo; N = 117. Infused IV immediately after cord clamped and 6 and 12 hrs later. Results of both treatment groups combined.
Outcomes	Febrile morbidity (oral temperature > 37.9oC twice at least 6 hrs apart after 1st 24 hrs); wound infection (redness, induration, tenderness and/or purulent discharge from the incision line); endometritis/parametritis (uterine and/or adnexal tenderness with fever) UTI (dysuria or pyuria and positive culture); need for antibiotic therapy (11% for treatment groups vs 27% for placebo); maternal length of stay (7.3 and 7.4 days for treatment groups vs 7.9 for placebo).
Notes	Side effects documented: 2 infusion‐related hypotensive episodes (1 with cefazolin, 1 with placebo that necessitated withdrawal from study); 6 episodes of phlebitis (5 in treated, 1 in placebo group); 1 episode of angioedema (placebo patient). Data provided on antibiotic resistance in wound isolates and screening cervical cultures. 1 episode of bacteremia (in placebo group); 1 episode of septic shock (in cefazolin‐treated group); both outcomes included as serious morbidity. Follow up at 6 weeks. Class of antibiotic: 1st generation cephalosporin or cefamycin (2nd generation cephalosporin). Subgroups: both elective and non‐elective CS; after cord clamping. The 3 groups were comparable regarding age, parity, gravidity, etc.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Randomly assigned". Comment: no description of sequence generation process.
Allocation concealment (selection bias)	Unclear risk	Comment: no information provided.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: 7 women (1 in treatment, 6 in placebo group) initially randomized but results not included, 6 because they failed to receive all 3 doses, 1 because of hypotensive episode with 1st dose. As‐treated analysis performed.
Selective reporting (reporting bias)	Unclear risk	Comment: insufficient information to judge.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Comment: double‐blind, placebo‐controlled.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: insufficient information to judge.
Other bias	Low risk	Comment: no other sources of bias identified.