Orwoll 1994.

Study characteristics
Methods	Trial design: randomised, double‐blinded, placebo‐controlled trial
Participants	Participants: 183 women were randomised and 137 analysed. Mean age:  31 years (range 17 to 46 years) Inclusion criteria: Symptomatic endometriosis, proved by laparoscopy Bone density measures during treatment Regular menstrual cycles for at least 3 months before enrolment Using a barrier method of contraception Exclusion criteria:  Therapy with danazol, androgenix hormones, oestrogens, progestins, glucocorticoids, GnRH agonists, or any other medication known to influence bone or mineral metabolism for at least 3 months before study > 2 ounces of alcohol per day Pregnant or breastfeeding Had a significant laboratory abnormality Setting: United States of America (9 academic medical centres) Timing: not stated
Interventions	200 μg of nafarelin intranasally twice per day for 6 months (n = 92)  versus 200 μg of nafarelin intranasally twice per day for 3 months followed by 3 months of placebo (n = 91)
Outcomes	Bone mineral density
Notes	Intention‐to‐treat analysis: yes Sample size calculation: not stated Funding: Supported by Syntex Laboratories, Inc Note: Drs. Orwoll and Hornstein have been salaried consultants for Syntex Laboratories, Inc. Author could not be contacted due to lack of information.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Subjects were randomised". No further details of method used to generate the randomisation sequence were provided.
Allocation concealment (selection bias)	Unclear risk	No details of method used to conceal allocation were provided.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Randomised, double‐blinded, placebo‐controlled trial
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Randomised, double‐blinded, placebo‐controlled trial
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not stated; appeared that all women included also were analysed
Selective reporting (reporting bias)	Low risk	The study protocol was not available but it was clear that the published reports included all expected outcomes, including those that were prespecified.
Other bias	Low risk	No other risk of bias detected