A two-arm parallel double-blind randomised controlled pilot trial of the efficacy of Omega-3 polyunsaturated fatty acids for the treatment of women with endometriosis-associated pain (PurFECT1)

Two-arm parallel double-blind randomized controlled pilot trial in women of reproductive age with surgically diagnosed endometriosis and associated pelvic pain. Seventeen participants were randomized to O-PUFA and 16 to olive oil placebo at the Royal Infirmary of Edinburgh in Scotland.

Omega-3-acid ethyl ester polyunsaturated fatty acids were given as one 1000 mg capsule twice daily for 8 weeks. The active supplement was compared with olive oil placebo in a two-arm double-blind randomized pilot trial.

O-PUFA did not produce a statistically significant improvement in pain scores or quality-of-life outcomes versus olive oil over 8 weeks. Both treatment groups showed a trend toward improvement in pelvic pain and quality of life, but between-group differences were not significant. Feasibility outcomes supported the conduct of a larger definitive multicentre trial, and no adverse events were reported. At 8 weeks, 14/17 in the O-PUFA group and 13/16 in the olive oil group completed follow-up.

This was a small pilot study with only 17 active-arm participants, limiting power to detect clinical effects. The intervention period was short at 8 weeks, and 6 participants were lost to follow-up overall. Results were also limited to a single center and a placebo choice that the authors noted may need refinement for a future trial.