Barrington 2003.

Methods	Number randomised: 50 Losses to follow‐up: 4 (2 in each group) No power calculation described Source of funding: not reported Years: not reported
Participants	Inclusion criteria: women with menorrhagia refractory to medical therapy Exclusion criteria: uterine cavity over 12 cm long, malignant or premalignant pathology (pre‐treatment endometrial biopsy taken)
Interventions	Surgery: thermal balloon ablation Medical treatment: LNG‐IUS
Outcomes	PBAC score Amenorrhoea
Notes	No measures of variance or tests of significance were reported for the change from baseline in each group nor for the difference in change between the groups: we have made attempts to contact the author for more data
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	High risk	Blinding not feasible. Our primary review outcomes are subjective and therefore susceptible to bias related to lack of blinding.
Incomplete outcome data (attrition bias) Primary outcomes	Low risk	All women received their allocated treatment. 44/50 analysed for primary outcome at 6 months. Reasons for withdrawal/dropout given.
Selective reporting (reporting bias)	Unclear risk	Adverse effects/tolerability not reported. Follow‐up only 6 months.
Other bias	High risk	PBAC scores significantly higher in the surgical group at baseline