Haitian-born Canadian boxer Adonis Stevenson suffered a "severe traumatic brain injury" and remains in intensive care, his doctors said on Wednesday, three days after the fighter lost his World Boxing Council light heavyweight title to Ukrainian Oleksandr Gvozdyk.

"Mr. Stevenson underwent surgery on the night of Saturday to Sunday and has since been admitted to the intensive care unit. He suffers from severe traumatic brain injury. His situation is still stable under the circumstances, but critical," said Dr Alexis Turgeon, the specialist physician at the Quebec City hospital, during a public update on Stevenson.

Adonis Stevenson
Stevenson (R) in his battle against Gvozdyk (L) on Saturday nightMathieu Belanger/Getty Images

"His condition requires mechanical respiratory assistance, deep sedation, and specialized neurological monitoring. It is too early to comment on Mr. Stevenson's long-term prognosis. I urge the media to be very cautious about distributing medical information that does not come from an official medical source."

Stevenson, who until Saturday, had not lost a match since 2010, was making his 10th title defence since winning the belt against Chad Dawson in 2013. He was, in fact, on course to winning his fight against Gvozdyk until the third round but lost momentum there on in.

In the 10th round, Gvozdyk gained more momentum before knocking out Stevenson along the ropes with a flurried combination in the 11th round. 

The 41-year-old Canadian boxer's fiancé Simone God, said she was at the hospital supporting her partner.

"He's a champion, he's a fighter, he's going to fight this," she said, according to Boxing Scene.

"We're partners in life and we're partners in business. He's resting right now, showing good signs, and we're hoping for the best. I have faith that he's going to be okay.

"We have good people here, we have support, and we're trying to keep it together for Adonis and to stay strong for our baby, Adonia."

Gvozdyk, who is only learning to speak in English, recorded a message for Stevenson.

Many around the boxing world have shared their concern on social media, including promoter Lou DiBella.

Gvozdyk, who won an Olympic bronze medal for Ukraine at the London 2012 Games, is now the World Boxing Council light heavyweight champion.