Methods	RCT, 3 parallel groups.
	Unit of randomization: individual.
Participants	Dates of collection: enrolment started November 1976.
	Setting: San Bernadino county and University of California at Los Angeles Medical Centers; primarily indigent cases
	Inclusion criteria: women undergoing CS.
	Exclusion: emergency section, penicillin allergy, fever > 38 degrees C, on antibiotics; declined to participate
Interventions	Ampicillin 1 g IV 15-30 minutes before surgery and at 2 and 8 hours post-operatively (N = 38) vs ampicillin 1 g IV immediately after cord clamping and at 2 and 8 hours post-operatively (N = 40) vs no antibiotic (N = 36). Outcomes of both treatment groups combined
Outcomes	Endometritis; wound infection; UTI; maternal hospital stay (5.1 and 4.7 for pre- and post-administration of antibiotics respectively vs 6.0 for no treatment, variance not given)
Notes	Although emergency CSs were excluded, the women enrolled did not conform to our definition of an elective section.
	Information on neonatal morbidity collected; there were 2 infants with definite infections in mothers who received no antibiotics and 1 infection in an infant where antibiotics were given after cord clamping
	Class of antibiotic: aminopenicillin (ampicillin).
	Subgroups: both elective and non-elective CS; before cord clamping (N = 38) and after cord clamping (N = 40).
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	“at random.”
		Method not described.
Allocation concealment?	Unclear	No information.
Blinding?	No	No blinding “…because of the different modes of administering the antibiotics, a double-blind study was not possible” Not placebo controlled.
All outcomes
		“The investigator was not intimately involved with the post-operative care … and the pediatricians did not know into which group the mothers had been placed.”
Incomplete outcome data addressed?	Yes	No loss of participants to follow up.
All outcomes		No participant excluded after randomization.
		ITT analysis.
Free of selective reporting?	Unclear	Insufficient information to judge.
Free of other bias?	Unclear	Insufficient information to judge.
Overall low risk of bias?	Unclear	Mostly unclear.