Methods	Randomized, placebo-controlled trial; 3 parallel groups.
	Unit of randomization: individual.
Participants	Dates of data collectin: no reported.
	Setting: 5 centres in Canada.
	Inclusion criteria: all women in labor or with ruptured membranes (duration of ruptured membranes not stated; mean duration 9.97 hours; included in both category)
Interventions	Cefoxitin 2 g (N = 124) vs cefazolin 1 g (N = 120) vs placebo (N = 117) infused IV immediately after cord clamped and 6 and 12 hours later. Results of both treatment groups combined
Outcomes	Febrile morbidity (oral temperature > 37.9°C twice at least 6 hours apart after first 24 hours); 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 bacteraemia (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: first generation cephalosporin or second generation cephalosporin
	Subgroups: both elective and non-elective CS; after cord clamping.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	“Randomily assigned.”
		No additional information.
Allocation concealment?	Unclear	No information provided.
Blinding?	Unclear	Described as “double-blind”.
All outcomes		No details provided on placebo.
Incomplete outcome data addressed?	Unclear	No loss to follow up reported.
All outcomes		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 first dose As-treated analysis performed.
Free of selective reporting?	Unclear	Insufficient information to judge.
Free of other bias?	Unclear	The 3 groups were comparable regarding age, parity, gravidity, etc.There was insufficient other information which to judge
Overall low risk of bias?	Unclear	All unclear.