Head injuries: More players will be advised to retire, says doctor
Increased awareness of concussion will mean more rugby players being advised to retire, says former World Rugby medical adviser Dr Barry O'Driscoll.
Wales sevens specialist Matthew Pewtner, 25, quit the game on Wednesday following a head injury.
He is the third Welsh professional player to retire in less than a year following concussions.
"We have moved on with our knowledge and we're more ready to advise players to retire," said Dr O'Driscoll.
"Every case of this saddens you and worries you just that little bit more.
"It does seem that with the much bigger impacts and speed of the game that these repeated sub-concussive and concussive knocks are becoming more damaging more frequently."
Pewtner's retirement came nearly seven months after he suffered a blow to the head playing for Newport Gwent Dragons in the Aviva Sevens in August 2015.
In May 2015 Dragons centre Ashley Smith announced he was quitting the game and in September ex-Wales back-row Jonathan Thomas retired after being diagnosed with epilepsy linked to head traumas suffered while playing.
George North incidents concern
The management of head injuries in rugby hit the headlines during the 2015 Six Nations Championship when George North played on for Wales after suffering two blows to the head against England.
That followed him missing a 2014 autumn international after suffering a concussion in a Test against New Zealand.
The Northampton Saints wing was eventually forced to take a break from the game following a further blow to the head in a game against Wasps.
Dr O'Driscoll - who has previously criticised rugby's concussion protocols - said the handling of players who have suffered multiple blows is a particular concern.
"I'm sure if [North] gets another one he will have to consider whether the worries about what the inference is from these is enough to make him give up the game," he said.
"It's his living and it's a very good living and he loves it ... and he would I'm sure and his advisers would make him think seriously about it.
"But it's a balance for each person to make and I don't think we're anywhere near the stage of the game of saying 'no, that's it, we can't pick you anymore', [because] we don't know enough yet.
"But any player at all who has had three or four concussions, in my opinion must seriously think about the future."
North made his comeback in Wales' win over Italy in September 2015 and scored an outstanding try in Wales' 27-24 win over Scotland on 13 February.