Chung 1995.

Methods	Trial design: parallel Single centre, UK
Participants	Couples with unexplained subfertility N randomised: 100 Age: IUI + OH 31.8 years (± 3.1); TI + OH 32.1 years (± 4.0) Duration of subfertility: IUI + OH 4.7 years (± 2.0); TI + OH 5.3 years (± 2.6) Basic fertility work‐up normal and semen 15 million motile per ejaculate Previous treatment: not stated
Interventions	Comparison: IUI + OH versus TI + OH Stimulation method: FSH 150 IU/day and GnRH nasal spray from day 21 on Ovulation: 5000 IU hCG when < 4 follicles > 16mm hCG post‐ovulatory for luteal support Timing TI: 24 hr + 48 hr after hCG Timing IUI: 36 hr to 48 hr after hCG Duration of treatment: 3 cycles max
Outcomes	PR per couple and per cycle Total delivered Multiple pregnancies Ectopic Miscarriage rate
Notes	ITT analysis: possible IUI was not possible on Sundays
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Blocked randomisation scheme
Allocation concealment (selection bias)	Low risk	Adequate; numbered sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding was not possible because of the nature of the interventions
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding was not possible because of the nature of the interventions and non‐blinding was not likely to affect the outcomes of interest
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	8/50 withdrawn and 6 treatment cycles cancelled in TI group, 4/50 withdrawn and 11 treatment cycles cancelled in IUI group. Reason for cycle cancellation was excessive response. Reason for withdrawal was not stated
Selective reporting (reporting bias)	Low risk	Live birth data and complication numbers were reported
Other bias	Low risk	Nothing detected