Bloomfield 1974.

Study characteristics
Methods	Multi‐arm RCT – 4 groups.
Participants	An homogenous population of postpartum women with moderate to very severe episiotomy pain (mediolateral or midline incision) within 48 hours of an uncomplicated delivery at the University of Cincinnati Medical Centre; homogenous population of postpartum women Women who were unmarried, < 18 years old (but included if married and < 18 years), with history of aspirin allergy, given analgesics or sedatives, or other psychotropic drugs in the previous 6 hours, breastfeeding and with known drug dependence were excluded
Interventions	Intervention: ibuprofen 300 mg (N = 20); ibuprofen 900 mg (N = 20) and aspirin 900 mg (N = 20) Comparison: lactose placebo (N = 20).
Outcomes	Changes in pain intensity (mean hourly PID scores, mean 6 hour summed PID scores) Pain relief (pain reduction > 50%) Side effects. Only 6‐hour data available in extractable format
Notes	Dates of study: NR Funding sources: United States Public Health Service Grant HL‐05622 and The Upjohn Company Declarations of interest: NR
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No clear statement on method used
Allocation concealment (selection bias)	Low risk	All treatments were in the form of film‐coated tablets identical in appearance and taste and pre‐packaged in coded number individual dose‐vials
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No clear statement
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data provided for all 80 participants (0% attrition rate in all groups)
Selective reporting (reporting bias)	Low risk	Prespecified outcomes were all reported
Other bias	Unclear risk	Some baseline differences between group characteristics (e.g. weight higher in group receiving ibuprofen 900 mg and more unmarried in ibuprofen 300 mg group). Chance occurrences, but with an uncertain influence on the results