Devroey 1978.

Study characteristics
Methods	RCT
Participants	Setting: Department of Obstetrics and Gynaecology, St Christiana Clinic, Dendermonde, Belgium Trial dates: not reported (published in 1977 and 1978) Inclusion criteria: primiparae who had undergone mediolateral episiotomy (3 cm to 5 cm) during the course of an otherwise uncomplicated birth within the previous 48 hours, with moderate to severe pain Exclusion criteria: a more extensive episiotomy (because of forceps birth or other procedures); multigravida women; known allergy to aspirin; breastfeeding; other analgesic therapy within the previous 6 hours; mild pain
Interventions	Aspirin (N randomised was unclear; N = 32 analysed) 600 mg; single oral dose in 2 identical capsules Placebo (N randomised was unclear; N = 31 analysed) Placebo; single oral dose in 2 identical capsules
Outcomes	Adequate pain relief as reported by the woman: the same trained nurse observer questioned women hourly for 6 hours; women estimated the severity of pain on a scale of 0 to 3 (0 = no pain; 1 = mild pain; 2 = moderate pain; 3 = severe pain): Mean pain scores were reported for each hour; the sum of the difference between these scores and pre‐treatment scores (SPID scores) were used to calculate 'Adequate pain relief as reported by the woman' (taken over 6 hours) The percentage of women who showed an improvement of at least 2 rating score points (i.e. from severe to mild; or from moderate to no pain) was also reported Need for additional pain relief in the first 48 hours for perineal pain: request for additional analgesic medication 4 hours after administration of study drugs Maternal adverse effects: close observation was made for any "adverse reactions"
Notes	Funding: "The statistical assistance of T. COOK, B. RODDA, and C. DAURIO of the Merck Sharp & Dohme Research Laboratories is gratefully acknowledged" Declarations of interests: not reported; though author affiliations include "Merck Sharp & Dohme Research Laboratories" Additional arms: this 5‐arm trial also assessed diflunisal 125 mg (N = 33 analysed), 250 mg (N = 30 analysed), and 500 mg (N = 30 analysed); we only included the relevant arms in this review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Patients were allocated at random"
Allocation concealment (selection bias)	Unclear risk	Not detailed
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quotes: "double‐blind"… "All test medications were prepackaged in individual patient‐coded vials containing a single oral dose in two identically appearing capsules"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Efficacy parameters and side‐effects were recorded by the investigator or by the same trained nurse observer, who questioned the patient at hourly intervals"
Incomplete outcome data (attrition bias) All outcomes	High risk	5/161 women admitted to the trial were excluded from the analysis: 2 as their initial pain was not considered severe enough to meet protocol; 2 due to incomplete data; 1 due to lack of cooperation (unclear from which groups; leaving 156 in total; 32 in the aspirin group, and 31 in the placebo group). 3 women in the placebo group were withdrawn at 4 hours because of severe pain, and 1 woman in the aspirin group at 3 hours for reasons unrelated to pain or the drug; women who dropped out of the study were included in the analysis; they were assigned a pain score of 4, worse than the scores of all women who remained in the study
Selective reporting (reporting bias)	High risk	Very limited outcome data reported; no access to trial registration or protocol to further assess selective reporting. Quote: "As pain relief was still very marked in the 500 mg diflunisal group at 6 hours, it was decided to extend the period of observation to 8 hours in 42 patients, who were approximately evenly distributed between the three groups"
Other bias	Unclear risk	Few baseline characteristics reported (initial pain score rating; age); limited methodological data reported