Murdoch 1991.

Methods	Trial design: parallel UK
Participants	Couples with unexplained subfertility N randomised: 39; IUI + NC 19; IUI + OH 20 Age: IUI + NC 30.5 years (± 3.1); IUI + OH 30.1 years (± 2.9) Duration of subfertility: IUI + NC 5.7 years (± 2.4); IUI + OH 5.1 years (± 1.9) Basic fertility work‐up done, semen normal (according to WHO 1987) Previous treatment: no
Interventions	Comparison: IUI + NC versus IUI + OH (vs GIFT) Stimulation method: 75 IU hMG/day and 200 micro gram buserelin 4 times daily intranasal Ovulation: 5000 IU hCG, when < 4 follicles of > 16mm were seen. Timing: 30 hr to 36 hr after hCG Natural cycle: IUI on alternate days until ovulation confirmed on USS Cycles were cancelled if > 4 dominant follicles were present Duration of treatment: 3 cycles max
Outcomes	PR per couple and per cycle Live birth Multiple pregnancies Clinical pregnancy defined by USS showing foetal heart activity
Notes	ITT analysis: yes Author provided additional information 1 pregnancy between treatment cycles 10 cycles were abandoned because no treatment available at the weekend
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random‐number sequence
Allocation concealment (selection bias)	Low risk	Adequate; sequentially numbered opaque 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	Drop‐out rate 3/19 (IUI + NC), and 2/20 (IUI + OH)
Selective reporting (reporting bias)	Low risk	Live birth data were provided
Other bias	Low risk	Nothing detected