Methods	RCT; 2 parallel groups.
	Unit of randomization: individual.
Participants	Dates of data collection: October 1976 and March 1977.
	Setting: Walter Reed Army Medical Center, Washington DC.
	Inclusion criteria: all women undergoing either primary or repeat CS (44% elective)
	Exclusion criteria: penicillin allergy; chorioamnionitis prior to surgery
Interventions	Ampicillin 1 g IV prior to surgery and 6 and 12 hours post-operatively (N = 26) vs placebo (N = 31)
Outcomes	Febrile morbidity (> 100.3 °F twice 6 hours apart after first 24 hours); endomyometri-tis (fever, uterine and abdominal tenderness, purulent lochia); UTI (positive culture); wound infection (induration, erythema and warmth with purulent drainage); need for antibiotics (treatment 3/26 vs placebo 13/31); maternal hospital stay (6.03 vs 6.9; no variance given)
Notes	Class of antibiotic: aminopenicillin (ampicillin).
	Subgroups: both elective and non-elective CS; before cord clamping.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	“In a … randomized manner.”
		Not further described, prepared by hospital pharmacy.
Allocation concealment?	Unclear	Prepared by the hospital pharmacy.
Blinding?	Yes	Double-blind, placebo controlled.
All outcomes		The pharmacist was the only individual with access to the treatment protocol
Incomplete outcome data addressed?	No	No losses to follow up were reported. 23/80 excluded because of errors in dispensation of medication
All outcomes		Analysis was not ITT; data from excluded patients could not be re-included
Free of selective reporting?	Unclear	Insuffient information to judge.
Free of other bias?	Unclear	“There is a notable difference in the division of repeat sections between groups”.
		There was insufficient other information which to judge
Overall low risk of bias?	No	Unclear sequence generation and concealment allocation, along with high exclusions