Bloomfield 1986b.

Study characteristics
Methods	Randomised controlled trial
Participants	Setting: single‐centre study at Cincinnati General Hospital ‐ time frame not given Inclusion criteria: hospitalised women with moderate or severe uterine cramp pain within 48 hours of an uncomplicated vaginal birth Exclusion criteria: women who experienced episiotomy pain greater than their uterine cramp pain; unmarried women less than 18 years of age; women with history of hypersensitivity to aspirin or other NSAIDs; women given analgesics, sedatives or other psychotropic within previous 4 hours; known drug dependence; women breastfeeding their babies.
Interventions	Following initial pain assessment women were randomly allocated to 1 of 4 treatment groups and given appropriate study medication on demand. Randomisation was stratified by initial pain intensity and by 1 of 2 nurse observers Ketorolac 5 mg (1 capsule 5 mg ketorolac and 1 placebo) (N = 30) Ketorolac 10 mg (1 capsule 10 mg ketorolac and 1 placebo) (N = 30) Aspirin 650 mg (2 capsules 325 mg aspirin) (N = 30) Placebo (2 capsules placebo) (N = 30)
Outcomes	Adequate pain relief as assessed by the woman: women were interviewed by 1 of 2 trained nurse observers before drug administration and ½ hour post‐treatment and then hourly for 6 hours. Pain intensity was measured on a 4‐point ordinal scale and pain relief on a 5‐point ordinal scale (not described). Women were asked to give a global rating of the medication at the final interview on a scale of 0 (worst) to 10 (best pain reliever ever taken). Pain intensity difference, SPID and mean total pain relief scores. Reported SPID scores were used to calculate 'adequate pain relief as assessed by the woman' (estimated over 6 hours). Need for additional analgesia: women requiring greater pain relief were removed from the study and given medication as needed, they were not interviewed further. Data for these women were included in the analysis Maternal side effects: women were questioned about side effects at the final interview with minimal leading questions and without a checklist
Notes	Dates of study: not stated Funding sources: Syntex Research. Ketorolac marketed by Syntex Inc in 1991 Declarations of interest: none stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Women were assigned using a "predetermined balanced randomisation schedule". "On enrolment, patients underwent two‐way stratification: first according to clinical nurse‐observer (morning or afternoon shift) and second, according to initial pain intensity (moderate or severe). Within each of these 4 strata, patients were allocated to 1 of 4 treatment groups according to a predetermined, balanced, randomization schedule that assured that all groups were of equal size and matched with respect to initial intensity of pain and nurse‐observers." Unclear exactly how random sequence was generated
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Capsules were identical in appearance and taste and were packaged in individual code numbered containers.."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data on all women randomised have been included in the reported outcomes. There were 30 women allocated to each of the groups. Including appropriately estimated data for the 10 women who withdrew. Seven women from the placebo group, and one woman each from the other three groups were withdrawn so that they could receive rescue analgesia. These women were not interviewed about pain following withdrawn. Subsequent pain intensity scores were adjusted to their pretreatment score and used in the analysis
Selective reporting (reporting bias)	Unclear risk	No protocol published or trial registration available
Other bias	Low risk	No other risk of bias identified