Frederick 1994.

Methods	Single centre study Randomisation by drawing numbers from a box. The numbers ranged from 1 to 20: when an odd number was drawn the patient received vasopressin, whereas an even number resulted in placebo being given Patients, care providers, and outcome assessors were blinded Power calculation: performed but study stopped half‐way and the code broken because of heavy bleeding in 10 patients No losses to follow up, and all patients were analysed in groups to which they were assigned Source of funding: not mentioned
Participants	Setting: university hospital, Kingston, Jamaica Inclusion criteria: symptomatic uterine myoma at least size of 14 weeks gestation Exclusion criteria: contraindication to vasopressin (notably cardiovascular and respiratory diseases) n = 20 Median age: 32 years (range 24‐40) Ethnicity: not described Sizes of fibroids: 5.3‐14.0 cm
Interventions	Treatment (n = 10): injection into the broad ligaments of 20 units/ml of vasopressin (i.e. 1ml diluted in 19 ml saline) made up at the time of surgery Control: n = 10, Injection of placebo (20 ml normal saline) Type of operation: laparotomy
Outcomes	Perioperative blood loss, blood transfusion
Notes	Indications for myomectomy: menorrhagia, recurrent miscarriage, subfertility Authors not contacted
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation by drawing numbers from a box
Allocation concealment (selection bias)	Unclear risk	Unclear
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete outcome data
Selective reporting (reporting bias)	Unclear risk	We do not have access to the study protocol
Other bias	Low risk	No other sources of bias identified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants and personnel were blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome assessors were blinded