Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Pain
Systematic review	42 women Data from 1 RCT	Menstrual symptom scores with fish oil capsules (twice daily for 1 month) with placebo (twice daily for 1 month) Absolute results not reported	P = 0.04	Effect size not calculated	fish oil
RCT 4-armed trial	78 women with primary dysmenorrhoea	Mean reduction in pain scores (measured on a 10 cm visual analogue scale) 0.15 cm with fish oil (0.5–1.0 g five times daily) for a minimum of 3 months 0.19 cm with placebo for a minimum of 3 months	P = 0.62		Not significant
Additional pain medication
Systematic review	42 women Data from 1 RCT	Mean number of tablets of ibuprofen (200 mg) taken 4.7 tablets with fish oil capsules (twice daily for 1 month) 10.1 tablets with placebo (twice daily for 1 month)	P = 0.015	Effect size not calculated	fish oil