Study	Reason for exclusion
Absalan 2013	Unclear from report whether trial was a RCT, and the authors did not respond to our request for further information.
Aflatoonian 2010	This article has been retracted from the literature at the request of the Editor and the ASRM Publications Committee.
Boostanfar 2016	Randomised a different intervention
Yang 2015	One‐third of participants chose to be in group 3 after randomisation. Not considered a properly randomised RCT.

ASRM: American Society for Reproductive Medicine RCT: randomised controlled trial