Thomas 1987.

Methods	Double‐blind RCT. Method of allocation not stated. Randomisation method not described. Attrition n=3, see quality table for details.
Participants	UK study, 40/98 eligible women. All 40 women were subfertile. Age range 21‐36 years. Endometriosis of all stages; primary or secondary infertility of > 12 months; cycle 25‐35 days with biphasic BBT; normal tubal anatomy by HSG and laparoscopy; normal sperm by WHO criteria; normal thyroid function and prolactin. There had to be no impediment to the collection of oocytes by the tubal fimbria.
Interventions	Gestrinone 2.5 mg twice weekly for 24 weeks, n=20 versus placebo, one tablet twice weekly for 24 weeks, n=20. Follow up for one year.
Outcomes	Cumulative pregnancy rates at 6 and 12 months; AFS score at second‐look laparoscopy in 36 women; pregnancy not reported by stage of disease.
Notes	Cumulative conception rates were reported on ITT basis. Other causes of infertility were excluded.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Randomly allocated but no details of randomisation procedure.
Allocation concealment?	Unclear risk	B ‐ unclear. No details of allocation concealment.
Blinding? All outcomes	Unclear risk	No details provided on who was blinded.
Incomplete outcome data addressed? All outcomes	Low risk	Three women from placebo group withdrew, no reasons provided.
Free of selective reporting?	High risk	Not followed up to live birth.