Methods	RCT; 3 parallel groups.
	Unit of randomization: individual.
Participants	Dates of data collection: initiated March 1981.
	Setting: Charlottesville, Virginia, USA, almost all were indigent women
	Inclusion criteria: both ‘low risk’ (labor < 6 hours) and ‘high risk’ (> 6 hours) women undergoing CS
	Exclusion criteria: allergy to penicillin or cephalosporin; antibiotic use within 7 days; antibiotics required for other reasons; pyrexia >38° C; foul amniotic fluid.
Interventions	Irrigation of the uterus and peritoneal cavity with 2 g cefamandole in 1000 ml normal saline (N = 73), vs saline placebo (N = 75) vs no irrigation group (N = 44). As the objective of this review is to compare antibiotic with no antibiotic, rather than the effect of irrigation, only the first 2 groups are compared (double blind comparison)
Outcomes	Metritis (pyrexia >38°C twice 8 hours apart, after 24 hours plus abnormal uterine tenderness, without another apparent source); duration of maternal stay (treatment 5. 29 days vs placebo 6.32 days, variance could not be calculated)
Notes	Authors’ definition of low and high risk do not correspond to those used for elective/ non-elective in this review.
	No treated patients developed evidence of drug reaction.
	There were no serious infections (pelvic abscess or phlebitis) in either group
	Class of antibiotic: second generation cephalosporin.
	Subgroup:
	both elective and non elective; after cord clamping.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	’A computer generated table of random numbers.”
Allocation concealment?	Yes	”Assigned under the direction of the hospital pharmacy.”
Blinding?	Yes	Partially double blind placebo-controlled (3 groups: antibiotic irrigation, saline placebo irrigation, no irrigation). Physicians were unaware ofthe type ofirrigation used
All outcomes
Incomplete outcome data addressed?	Yes	No loss to follow up reported.
All outcomes		No participants excluded.
		ITT analysis.
Free of selective reporting?	Unclear	Insufficient information to judge.
Free of other bias?	Unclear	The groups were comparable regarding gra-vidity, parity, maternal weight, hematocrit, etc. There was insufficient other information which to judge
Overall low risk of bias?	Yes	Good sequence generation, concealment allocation, blinding and complete outcome data