Bettigole 1981.

Study characteristics
Methods	Randomised controlled trial
Participants	Setting: Massachusetts, USA, no information about time frame of study Inclusion criteria: postpartum women aged 46 years or less with acute uterine cramp pain, review authors have assumed women had vaginal delivery. Women gave informed consent Exclusion criteria: women who had received analgesics in the preceding 4 hours
Interventions	Following initial pain assessment women were randomly allocated to 1 of 3 treatment groups: Treatment group 1 received 2 doses of placebo 4 hours apart; each dose was 1 capsule and its composition is not stated (N = 12) Treatment group 2 received 2 doses of codeine sulfate 60 mg 4 hours apart; each dose was 1 capsule (N = 11) Treatment group 3 received 2 doses of fenoprofen 200 mg 4 hours apart; each dose was 1 capsule (N = 12)
Outcomes	Adequate pain relief as reported by the woman: pain assessed by an observer before the 1st dose and at hourly intervals for 8 hours Women were asked to rate pain intensity on a 5‐point scale; no pain (0), a little (1), some (2), a lot (3), terrible (4) and pain relief on 5‐point scale; no relief (0), a little (1), some (2), a lot (3), complete relief (4). Pain intensity difference was calculated for each observation and summed and pain relief scores were summed. Mean pain intensity difference and mean pain relief score for each hourly observation and SPID mean and mean total relief as assessed by the observer. SPID scores were used to calculate 'adequate pain relief as reported by the woman' (estimated over 8 hours) Maternal adverse events: after the final pain observation at 8 hours women were asked to report on adverse drug reactions from a checklist which included; drowsiness, dizziness, asthenia, headache, abdominal discomfort, hidrosis, nausea, vomiting, tinnitus, tremor, tachycardia, blurred vision, hypertension, nervousness, itching/rash, edema, dry mouth.
Notes	Paper does not state how many women were randomised Dates of study: not stated Funding sources: not stated Declarations of interest: no declaration of interests statement
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study medications were "prescribed in random order".
Allocation concealment (selection bias)	Unclear risk	Concealment not stated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Study medication was presented as "capsules of identical appearance". Study described as double‐blind, but unclear who was blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Study described as double‐blind, but unclear who was blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The number of women who were randomised is not given. Includes only participants for whom complete data were available. Baseline demographics and results include 35 women with pain from uterine cramping
Selective reporting (reporting bias)	Unclear risk	No protocol published or trial registration available
Other bias	Unclear risk	Unclear if randomisation was stratified by source of pain; uterine cramp or episiotomy although data analysed separately