Methods	Randomized, placebo-controlled trial; 3 parallel groups.
	Unit of randomization: individual.
Participants	Dates of data collection: September 1980 to November 1981.
	Setting: Hopital Saint-Luc, Montreal, Canada.
	Inclusion criteria: women undergoing non-elective CS.
	Exclusion criteria: not in labor with intact membranes, allergy to cephalosporins, antibiotic use within 48 hours, fever, ruptured membranes for > 36 hours
Interventions	Cefoxitin 2 g IV (N = 30) vs cefazolin 1 g IV (N = 30) vs placebo (N = 29) at clamping of the cord and at 6 and 12 hours later. Both treatment groups have been combined
Outcomes	Endometritis, wound infection, UTI (symptoms or two successive positive cultures) septicemia, pelvic abscess, pelvic thrombophlebitis. Follow up at 6 weeks. No side effects observed
Notes	There were no serious infections in any of the groups.
	In the placebo and cefazolin groups there was no increase in aerobic bacterial colonization of the cervix after 4 days but there was an increase in colonization by anaerobes; the opposite occurred in the group receiving cefoxitin
	Class of antibiotic: first generation cephalosporin vs second generation cephalosporin (cefamycin)
	Subgroups: non-elective CS; after cord clamping.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Randomized; method not described.
Allocation concealment?	Yes	“A number (1 to 90) identified the boxes. The number was allocated randomly to a box.”
		An envelope containing the randomization code was available in case of adverse reactions
Blinding?	Yes	Described as “double blind”.
All outcomes		Placebo-controlled: “vitamin solution with a similar colour as the other preparations”
Incomplete outcome data addressed?	Unclear	No loss to follow up.
All outcomes		1 patient in the control group was excluded from analysis as no cultures were performed As treated analysis performed.
Free of selective reporting?	Unclear	Insufficient information to judge.
Free of other bias?	Unclear	The groups were comparable regarding demographic characters.
Overall low risk of bias?	Unclear	Mostly unclear.