Bloomfield 1967

Methods	Multi‐arm RCT ‐ 5 groups.
Participants	All women having a painful mediolateral episiotomy, an uncomplicated labour and delivery, and consenting to take an investigational drug in the obstetric service of Cincinnati General Hospital. The study was conducted between December 7th 1965 and April 22nd 1966. Women who were breastfeeding, were under age 18 and were known to have ASA sensitivity were excluded.
Interventions	Intervention: chlorphenesin 400 mg (N = 16); chlorphenesin 800 mg (N = 16); chlorphenesin 400 mg + ASA 300 mg (N = 18) and ASA 600 mg (N = 16). Comparison: placebo (N = 18).
Outcomes	Pain intensity (0 indicating no pain (none), 1 slight pain (a little), 2 moderate pain (medium), and 3 severe (a lot)). Side effects. ASA 300 mg were the only data used in the review as the other drug treatment regimens were not NSAIDs. Pain intensity was measured immediately before treatment and then hourly for 6 hours after administration.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomly assigned under controlled conditions but does not state how sequence was generated.
Allocation concealment (selection bias)	Low risk	Coded medication; identical black capsules.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind; code could be broken without revealing the treatment received by other patients.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No clear statement.
Incomplete outcome data (attrition bias) All outcomes	Low risk	5% attrition rate (1 of 16 women) in the ASA 600 mg group; 0% attrition in the placebo group (N = 18).
Selective reporting (reporting bias)	Low risk	Pre‐specified outcomes were all reported.
Other bias	Unclear risk	Potential carry‐over of effect of intrapartum analgesia.