Waldenström 1998.

Methods	Randomized controlled trial
Participants	Country: Sweden Female infertility Mean age: 32 years (range 25–40 years) n=47 recruited Inclusion criteria: infertile women with known indications for standard  IVF Exclusion criteria: infertility with male factors, poor responders
Interventions	Short time sperm exposure (1.5‐2h) versus   long time sperm exposure (16‐18h)
Outcomes	Clinical pregnancy rate, fertilization rate, polyspermy rate
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Patients were randomized to two treatment groups. How randomization performed was not mentioned
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete outcome data
Selective reporting (reporting bias)	Unclear risk	Did not report live birth, the primary outcome of the review
Other bias	Unclear risk	Can not definitively assess other bias
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Not stated, but the review authors considered that blinding was not likely to influence the risk of performance bias for the primary review outcome and secondary outcomes
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not mentioned, but the review authors judged that the outcome measurement was not likely to be influenced by lack of blinding