de Souza 2010.

Study characteristics
Methods	Parallel group RCT, single centre No. of women randomised: 58 No. of women analysed: At 12 months, 55 (1 woman in Mirena group and 2 women in balloon group required hysterectomy). At 5 years, 52 (1 woman required hysterectomy and 3 were lost to follow‐up in Mirena group but 27/30 were analysed; 6 women required hysterectomy and 3 were lost to follow‐up in balloon group but 25/28 were analysed) Power calculation for sample size: difference of > 40% between proportions, but this calculation did not allow for dropouts ITT analysis but did not take dropouts into account Funding: Bayer provided the materials used in the study (both interventions)
Participants	Country: Brazil Women recruited between January 2005 and March 2007, with mean age 42 and 44 years and baseline PBAC 542 and 420. Inclusion criteria Clinical HMB refractory to medical treatment (OC, HT, NSAIDs) 3‐month washout period, regular menstrual cycles Age ≥ 35 years Menstrual blood loss > 80 mL (as measured by PBAC) Negative pregnancy test Uterine volume < 200 mL (as measured by transvaginal sonogram) Negative Pap smear within past year No intracavity abnormalities, pelvic inflammatory disease, suspected endometrial pathology, abnormal endometrial histology, previous endometrial resection and ablation, or any other pathology for which hysterectomy would be appropriate Women were required to have completed their families Exclusion criteria: not reported
Interventions	(1) Levonorgestrel‐releasing IUS (Mirena) (2) Thermal balloon ablation (Thermachoice) under general anaesthesia Both procedures initiated during the first 15 days of a menstrual cycle
Outcomes	Menstrual blood loss (PBAC score) Other bleeding outcomes (amenorrhoea, decreased bleeding) Hb levels Quality of life (Psychological General Wellbeing Index) Failure of treatment Satisfaction rates Assessed at 1, 6 and 12 months after the procedures and additionally at 5 years
Notes	2 publications: 1 assessed outcomes at 12 months and the other at 5 years after treatment
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "computer generated randomisation list"
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded, lack of blinding likely to influence 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 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	Unclear risk	At 12‐month assessment, minimal dropouts but at 5 years' assessment only 17/30 in Mirena group and 11/28 in balloon group were still premenopausal and evaluated for Hb, quality of life scores and bleeding pattern
Selective reporting (reporting bias)	Unclear risk	Adverse events not prespecified or reported
Other bias	Low risk	Groups appeared comparable at baseline