Methods	Randomized placebo-controlled trial; 2 parallel groups.
	Unit of randomization: individual.
Participants	Dates of data collection: January 1970 to June 1980.
	Setting: Washington, DC. US.
	Inclusion criteria: women undergoing CS who were not in labor and did not have ruptured membranes (elective)
Interventions	Ampicillin 1 g 30 min prior to surgery and at 4 and 8 hours post-operatively (N = 42) vs placebo solution (N = 40)
Outcomes	Febrile morbidity (> 100.4 °F twice 6 hours apart after the first 24 hours); endomy-ometritis (fever, uterine and adnexal tenderness, purulent lochia); UTI; wound infection (induration, erythema and warmth with purulent drainage); need for antibiotics (treatment 1/42 vs placebo 6/40); maternal hospital stay (4.3 vs 4.6; no variance given)
Notes	No life-threatening infection related complications nor bacteremic episodes in either group
	Class of antibiotic: aminopenicillin (ampicillin).
	Subgroups: elective CS; before cord clamping.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Randomized.
		No further information.
Allocation concealment?	Unclear	No information was provided.
Blinding?	Unclear	Described as “double-blind”. Placebo-controlled: “placebo solution”.
All outcomes
Incomplete outcome data addressed?	Yes	No loss to follow up.
All outcomes		No participant excluded.
		ITT analysis.
Free of selective reporting?	Unclear	Insufficient information to judge.
Free of other bias?	Unclear	The 2 groups were comparable regarding age, race, gravidity, parity and socioeconomic status. There was insufficient other information which to judge
Overall low risk of bias?	Unclear	Mostly unclear.