Sepulveda 2011.

Methods	Prospective, randomised controlled trial
Participants	100 recipients from an oocyte donation program, undergoing either IVF or ICSI were randomised into a treatment group (n=47) or a control group (n=44). 9 participants were excluded for medical reasons after randomisation. All oocytes derived from donor women.
Interventions	Oocytes and embryos were cultured at 5% O2 or atmospheric (20%) O2 concentration. Embryo transfer was performed on Day 5/6 of embryo development.
Outcomes	Clinical pregnancy rate (reported as positive beta hCG pregnancy test), multiple pregnancy rate, implantation rate, embryo development rate, cryopreservation rate, fertilisation rate, blastocyst expansion rate and MCI Grade A blastocysts rate.
Notes	Location: Lima, Peru Setting: Grupo PRANOR de Reproduccion Asistida Additional information regarding the study was obtained after contacting the authors No commercial funding Additional outcomes: Implantation rate: low oxygen: 38/91, high oxygen 32/87 Embryo development rate: low oxygen 205/370, high oxygen 161/385 Cryopreservation rate: low oxygen 114/370, high oxygen 74/385
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation into treatment or control group according to a computerised randomisation list
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment has not been specified
Blinding (performance bias and detection bias) All outcomes	Low risk	Clinicians and participants were blinded for allocation
Incomplete outcome data (attrition bias) All outcomes	High risk	Loss to follow up has been accounted for. No live births reported, no intention‐to‐treat analysis
Selective reporting (reporting bias)	Low risk	Outcomes were reported in a prespecified fashion
Other bias	Low risk	Reporting multiple pregnancies whilst adhering to a multiple embryo transfer policy