Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
Systematic review	Women with primary dysmenorrhoea	Adverse effects with aspirin with placebo Absolute results not reported	RR 1.3 95% CI 0.79 to 2.17		Not significant
Systematic review	Women with primary dysmenorrhoea	Nausea with aspirin with placebo Absolute results not reported	RR 1.66 95% CI 0.59 to 4.67		Not significant
Systematic review	Women with primary dysmenorrhoea	Dizziness with aspirin with placebo Absolute results not reported	RR 1.29 95% CI 0.28 to 5.89		Not significant
Systematic review	Women with primary dysmenorrhoea	Headache with aspirin with placebo Absolute results not reported	RR 0.60 95% CI 0.18 to 2.04		Not significant
Systematic review	Women with primary dysmenorrhoea 2 RCTs in this analysis	Gastrointestinal adverse effects with aspirin with placebo Absolute results not reported	OR 1.41 95% CI 0.55 to 3.60 P = 0.48		Not significant
Systematic review	96 women Data from 1 RCT	Neurological adverse effects with aspirin with placebo Absolute results not reported	OR 3.66 95% CI 0.75 to 17.78 P = 0.11		Not significant