Tahara 2000.

Study characteristics
Methods	Trial design: Prospective, randomised, longitudinal pilot study
Participants	Participants: 15 women were randomised and analysed. Mean age:  Control group: 35.2 ± 2.6 years Half‐dose group: 34.7 ± 5.7 years Inclusion criteria: Symptomatic endometriosis who were candidates for 6 months of GnRH agonist therapy Diagnosis of endometriosis was confirmed by laparoscopy or laparotomy Menstruated regularly Normal hepatic and renal function Exclusion criteria:  No recent medical treatment for endometriosis Not taking medications known to affect bone metabolism Setting: Japan Timing: not stated
Interventions	Control group: full‐dose intranasal nafarelin treatment (200 μg twice daily) for 24 weeks (n = 7) versus Half‐dose group: full dose intranasal nafarelin treatment (200 μg twice daily) for 4 weeks followed by half‐dose intranasal nafarelin treatment (200 μg daily) for 20 weeks (n = 8)
Outcomes	Symptoms of endometriosis (dysmenorrhoea, dyspareunia, and pelvic pain) Vasomotor symptoms (hot flashes or dizziness) Bone mineral density Fasting serum and urine samples
Notes	Intention‐to‐treat analysis: not stated Sample size calculation: not stated Funding: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The patients were assigned, using a random number table, to two groups.
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	Unclear risk	No details provided of blinding of participants or personnel
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details provided of blinding of outcome assessment
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses to follow‐up
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