Rugby's governing body is investigating whether 'all concussion protocols' were followed by Wales during their management of wing George North in their Six Nations loss to England.
The 22-year-old suffered heavy head blows in each half, but finished Friday's 21-16 loss to Stuart Lancaster's charges, passing tests during and after the match in Cardiff.
The Welsh Rugby Union has claimed that the second incident was not seen at the time and even though North currently "has no signs and symptoms", they are treating him as concussed after studying video footage.
A statement on World Rugby's website reads: "Having undertaken an initial review of the broadcast footage, World Rugby is seeking to establish from the WRU whether all concussion management protocols were appropriately followed.
"Concussion management and education is at the heart of World Rugby's player welfare strategy designed to protect players at all levels of the game and promote the very highest standards of education, coaching and medical care."
Wales also confirmed that tight-head prop Samson Lee was concussed in the competition's opening game at the Millennium Stadium.
