Pago Pago, AMERICAN SAMOA — Mouth-guards that light up when a player sustains a significant head impact will be used at this year's women's Rugby World Cup, which starts next week.

The mouth-guards, which use LED lights, will flash red if the impact is severe enough to potentially cause a concussion.

The referee will then stop play with the player sent off for a head injury assessment.

The mouth-guards will be introduced to the men's Rugby Championship next year.

The technology was trialed in this year's Major League Rugby and is the latest version of "smart mouthguard".

World Rugby science and medical manager Dr Lindsay Starling said the new system was better than the current one, which uses Bluetooth to flag severe impacts.

Under the current system the alerts can take several seconds to reach the match day doctor.

"Match officials and players will be able to see that this player has sustained a big head impact because their mouth guard is flashing red," Starling said.

"It will create awareness about head injuries and concussions in the stands and for fans at home, being able to see it on TV."