Kilic 2009.

Study characteristics
Methods	Single centre, parallel group RCT No. of women randomised: 40 No. of women analysed: 40 Power calculation for sample size: 9 per group for 80% power to detect a 20% decrease in the PBAC score with SD 14 ITT analysis Funding: not stated
Participants	Country: Turkey Women taking anticoagulant therapy after cardiac valve replacement, with median age 36 years. Inclusion criteria Women with a complaint of HMB and PBAC score > 185 Exclusion criteria: not reported
Interventions	LNG‐IUS inserted during the first 3 days of menstrual bleeding ‒ antibiotic prophylaxis used Control ‒ observation
Outcomes	Primary Menstrual blood loss (measured by PBAC) Secondary Hb, haematocrit and ferritin levels
Notes	HMB is a potential side effect of treatment with anticoagulant therapy
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "simple randomisation method" but this method was not described
Allocation concealment (selection bias)	Unclear risk	Quote: "closed envelopes" ‒ insufficient information to know whether allocation was properly concealed
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding, lack of blinding likely to influence outcome
Blinding of participants and personnel (performance bias) Haematin alkaline, Haemoglobin All outcomes	Low risk	No blinding, lack of blinding unlikely to influence outcome
Blinding of outcome assessment (detection bias) All outcomes	High risk	No blinding, lack of blinding likely to influence outcome
Blinding of outcome assessment (detection bias) (Haematine alkaline and haemoglobin) All outcomes	Low risk	No blinding, lack of blinding unlikely to influence outcome
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "all participants completed the study"
Selective reporting (reporting bias)	Unclear risk	Adverse events not assessed
Other bias	Low risk	Groups appeared comparable at baseline ‒ no other potential bias