Methods	RCT; 3 parallel groups.
	Unit of randomization: individual.
Participants	Dates of data collection: February to June 1982.
	Setting: Kaiser-Permanente Medical Center-Santa Clara, California
	Inclusion criteria: all women undergoing CS (39/128 repeat section)
	Exclusion: fever or infection, allergy to antibiotics.
Interventions	Cefoxitin 2 g in 1 L saline irrigation (N = 41) vs cephapirin 2 g in 1 L saline irrigation (N = 44) vs identical appearing placebo saline irrigation (N = 43) after delivery of the placenta; both treatment groups combined in the analysis
Outcomes	UTI (positive culture); wound infection (purulent wound discharge with or without wound separation); endometritis (fever > 100.4°F after first post-operative day, uterine tenderness, foul smelling lochia without other source)
Notes	Follow up for 8 weeks.
	1 patient in placebo group developed septic pelvic thrombophlebitis and septic pulmonary emboli, classified as a serious complication
	Class of antibiotic: first generation cephalosporin or second generation cephalosporin (cefamycin)
	Subgroups: type of CS unclear; after cord clamping.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	“Sequenced randomly by lottery method.”
Allocation concealment?	Yes	“1 milliliter of multivitamin infusion was added to create an identical appearance of all solutions .… and bags sequenced randomly … used in numerical order.”
Blinding?	Yes	“Patients, physicians, operative room personnel and data collectors were… blinded to the group assignment.”
All outcomes
Incomplete outcome data addressed?	Yes	No loss to follow up reported.
All outcomes		4 patients were eliminated from the statistical analysis because ofdeviations from the protocol of irrigation technique Not ITT analysis. Data could not be re-included in the analysis
Free of selective reporting?	Unclear	Insufficient information to judge.
Free of other bias?	Unclear	There were no statistically significant differences in mean gestational age, mean number of vaginal examination or mean duration of ruptured membranes between groups. There was insufficient other information which to judge
Overall low risk of bias?	Yes	There is low risk of bias for the 4 major components.