Shaw 2007.

Study characteristics
Methods	Single centre, parallel group RCT No. of women randomised: 66 No. of women analysed: 50 (completers at 12 months) – fewer women analysed because treatment failures not counted Power calculation for sample size: 30 women per group to have 80% power to detect a 50‐point difference in PBAC scores between treatments Analysis was not by ITT (no method to account for missing data) Funding: ATOS Medical provided balloons and partly funded research nurse sessions
Participants	Country: UK Women with idiopathic menorrhagia in whom prior medical oral treatment had failed: mean age 42 or 43 years Inclusion criteria Aged 25 to 49 years Family complete Failed on appropriate first line oral medical therapy Normal histology on Pipelle endometrial biopsy No pathology on pelvic ultrasound Normal cervical smear PBAC score >120 (mean of two control cycles) Exclusion criteria Previous LNG‐IUS Previous endometrial resection/ablation Abnormal uterine bleeding not fully investigated Other pathology where hysterectomy was indicated Submucous fibroid identified on scan or hysteroscopy Uterine cavity < 7 cm or > 11 cm
Interventions	LNG‐IUS (Mirena) inserted in the uterine cavity just following menstruation Thermal balloon ablation (Menotreat) – undertaken under general anaesthesia post menstruation without routine pretreatment
Outcomes	Primary PBAC scores at 12 months Secondary PBAC scores at 3, 6 and 9 months Changes in Hb and ferritin concentrations between baseline and 6 months Patient satisfaction Continuance of the method at 2 years Hysterectomy rates at 2 years Teatment failure (additional medical treatment required, expulsion or removal of LNG‐IUS or total abdominal hysterectomy) Follow‐up 3, 6, 9, 12 and 24 months
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "computer generated balanced random number blocks"
Allocation concealment (selection bias)	Low risk	Quote: "sequentially sealed opaque envelope" opened only when patient had signed the consent form
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded, lack of blinding likely to influence the outcome
Blinding of participants and personnel (performance bias) Haematin alkaline, Haemoglobin All outcomes	Low risk	Not blinded, lack of blinding unlikely to influence the outcome
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not blinded, lack of blinding likely to influence the outcome
Blinding of outcome assessment (detection bias) (Haematine alkaline and haemoglobin) All outcomes	Low risk	Not blinded, lack of blinding unlikely to influence the outcome
Incomplete outcome data (attrition bias) All outcomes	High risk	Substantial attrition from trial by 12 months
Selective reporting (reporting bias)	Low risk	All prespecified outcomes reported
Other bias	Low risk	Groups appeared balanced at baseline and no other potential bias