Wright 2004a.

Methods	Design: parallel (2 arms) Country: Chile Multisite: no International: no Treatment duration: unclear Follow‐up: unclear Rate of ascent (m/h): unclear Final altitude reached: 4680 m AMS scale: Lake Louise self‐reporting AMS questionnaire
Participants	20 healthy participants. No additional information provided Exclusion criteria: not stated Participants were randomized to Medroxyprogesterone group (10; 50%) Placebo group (10; 50%) None of the participants randomized were excluded from analysis Main characteristics of participants Age (years): range 24 to 59 years Percentage of men: 85% Body mass index: not reported
Interventions	Medroxyprogesterone group (intervention): administration of medroxyprogesterone 30 mg twice daily Placebo group (control): administration of 30 mg ascorbic acid twice daily
Outcomes	Outcomes were not pre‐defined as primary or secondary AMS incidence using Lake Louise self‐reporting AMS questionnaire AMS symptoms Blood gases Cerebral regional oxygen saturations
Notes	Trial registration: not stated Sponsor: The Wellcome Trust, the Arthur Thompson Trust, the Mount Everest foundation, Ciba Corning Diagnostics UK and Upjohn Ltd Role of sponsor: not stated A priori sample size estimation: no Conducted: not stated Declared conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information to score this item as low or high risk of bias Quote: "...were randomly allocated (...) Randomization was performed independently by the hospital pharmacy" Page 26
Allocation concealment (selection bias)	Unclear risk	Quote: "randomization was performed independently by the hospital pharmacy" Page 26
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to score this item as low or high risk of bias
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to score this item as low or high risk of bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	No participants were lost at follow‐up
Selective reporting (reporting bias)	High risk	Patient‐important outcomes, such as adverse events, were not reported
Other bias	Unclear risk	Unclear if intervention was administered before or during the ascent, or both