Aghajanpour 2017.

Methods	RCT
Participants	Women with recurrent implantation failure
Interventions	Study group: endometrial sampling performed once in the follicular phase and again in the luteal phase (two procedures) Control group: endometrial sampling performed once in the luteal phase (one procedure)
Outcomes	No pregnancy outcomes reported
Notes	Only 20 women recruited in total and outcomes focused on VEG expression; no pregnancy data available NCT02480127 Authors confirmed recruitment is completed but report not yet available, in July 2020 (sama.aghajanpour@yahoo.com)