Zafardoust 2017.

Study characteristics
Methods	Study design: single‐centre RCT Country: Iran Setting: fertility clinic Sponsorship source: infertility and recurrent abortion treatment centre of Avicenna Trials registry number: www.irct.ir/trial/11703 (registered during recruitment)
Participants	Inclusion criteria: couples undergoing treatment with their own gametes, women aged < 40 years old, women with at least 4 good‐quality embryos after thawing (grade A), women who had not had more than 1 previous embryo transfer Exclusion criteria: cycles requiring pre‐implantation genetic diagnosis, women with an anatomic disorder of the uterus or hydrosalpinx/hydrosalpinges Number of participants randomised to each arm of the study: number randomised to each arm before dropout was not disclosed Group differences: the average age between the 2 groups differed Fresh or frozen cycle?: frozen cycles IVF or ICSI?: ICSI Length of time exposed to intervention medium: from embryo thawing through to embryo transfer Trade name and concentration of GM‐CSF in intervention medium: BlastGen 2 ng/mL Trade name of control medium: Vitrolife, USA Day of embryo transfer: not disclosed Number of embryos transferred: not disclosed
Interventions	Intervention: GM‐CSF‐supplemented culture medium Control: standard IVF medium
Outcomes	Clinical pregnancy rate
Notes	Emailed on 29 October 2019, 26 November 2019, and 9 January 2020 for further information, but received no response
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No description of how randomisation was undertaken
Allocation concealment (selection bias)	Unclear risk	No description of how allocation concealment was undertaken
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No description of who, if anyone, was blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding of outcome assessors not described
Incomplete outcome data (attrition bias) All outcomes	High risk	10 women were not included in the final analysis, which is a high rate of attrition.
Selective reporting (reporting bias)	High risk	No data on miscarriage, multiple pregnancy, and beta human chorionic gonadotrophin (BHCG) levels, which are secondary outcomes noted on trials register
Other bias	High risk	Small sample size of 90 participants