Boxing star Claressa Shields has been suspended by the Michigan Unarmed Combat Commission after testing positive for marijuana.

The three-weight undisputed champion, 29, tested positive for the drug via an ‘oral fluid sample’ after her win over Danielle Perkins on February 3.

Shields now faces a probe from the Michigan Commission while the World Boxing Organization (WBO) has requested a ‘show notice’ from the fighter.

Marijuana is banned by the World Anti-Doping Agency (WADA) with Shields strongly insisting last week that she was a ‘clean athlete’ on social media.

In a statement, the Michigan Commission said: ‘Ms Shields’ conduct as a licensed professional boxer constitutes an imminent threat to the integrity of professional boxing, the public interest, and the welfare and safety of professional athletes.’

Shields’ victory over Perkins in Michigan earlier this month was historic as she became the first boxer – male or female – to win undisputed titles in three different weights in the four-belt era.

The American is a two-time Olympic gold medallist with middleweight triumphs at London 2012 and Rio 2016 respectively.

It should be noted that while the WBO has asked Shields to explain herself, the sanctioning body does not have the power to suspend fighters.

Shields, undefeated in 16 professional bouts, was left delighted after she made boxing history against heavyweight Perkins this month.

‘It feels unbelievable,’ she said. ‘I had a really hard training camp. And just last Friday I tore my labrum in my left shoulder, so I wasn’t able to use my good jab.

‘But I didn’t want to call the fight off because I had asked God to give me a big fight in my hometown. He did that. So I decided to keep going through with it.

‘I feel so happy. And shout out to my opponent, Danielle Perkins. Man, that girl was strong as hell.’

Shields often refers to herself as the ‘GWOAT’ – Greatest Woman of All Time.

‘I believe that I decided I was the ‘Greatest Woman of All Time’ when I won my second Olympics,’ Shields told DAZN’s Off the Cuff in 2023.

‘People talking about things that are impossible, what they told me was winning two Olympic gold medals in boxing is near impossible.

‘So, when I won, you all said I couldn’t do that, and I did so that day I was like ‘I am the Greatest Woman of All Time’. I just told the world.

‘And from that day I have pushed myself to just be better, to live up to that standard because Muhammad Ali always proved the doubters wrong.’

American Claressa Shields is under investigation after testing positive for marijuana following her win over heavyweight Danielle Perkins on 3 February in Michigan.

The 29-year-old – who is a three-weight undisputed champion – has been suspended from fighting in the state by the Michigan Unarmed Combat Commission.

Shields tested positive after providing an “oral fluid sample” after the fight.

Marijuana is banned in-competition by the World Anti-Doping Agency (Wada).

American sprinter Sha’Carri Richardson missed the Tokyo Olympics in 2021 after receiving a one-month ban following a positive drugs test for marijuana.

The WBO, which is a sanctioning body and does not have the power to suspend boxers, has requested a “show notice” from Shields, asking her to explain herself, while the Michigan Commission has opened its own investigation into whether she should face disciplinary action.

“Ms Shields’ conduct as a licensed professional boxer constitutes an imminent threat to the integrity of professional boxing, the public interest, and the welfare and safety of professional athletes,” the Michigan Commission said.

Last week, Shields addressed rumours of a failed drugs test on social media, saying she was a “clean athlete”.

BBC Sport has contacted Shields for comment.

Under the WBC’s clean boxing programme, Shields and Perkins would have been subject to drug testing by the Voluntary Anti-Doping Agency (Vada).

Shields won gold at the Olympics aged 17 and has won titles in multiple weights as a professional boxer.

She is undefeated in 16 fights and was the first boxer, male or female, to win undisputed titles in three different weights in the four-belt era.

Claressa Shields provides bleak update about her MMA career after 2-1 run: ‘Not enough time’

Boxing superstar Claressa Shields’ MMA career might be coming to an abrupt end just three fights into her PFL tenure.

Claressa Shields is arguably one of the greatest boxers, male or female, to compete in the ring in the sport’s decorated history. After earning a slew of world championship belts, Shields opted to leap into MMA, which drew significant hype from fans, fighters, and pundits.

Shields appeared to live up to the hype when she finished Brittney Elkin in come-from-behind fashion during her 2021 PFL and professional MMA debut. Talks of a potential fight between then-PFL superstars Kayla Harrison and Shields began to surface, and the debate of who would get the better of the other in the cage ramped up.

But Shields faced her first significant case of adversity in MMA in her following fight against Abigail Montes at the 2021 PFL World Championship. She lost to Montes by split decision and struggled mightily with her ground game.

After bouncing back against Kelsey DeSantis last February, Shields seemed intrigued at potentially getting more activity in MMA over boxing. But her recent remarks potentially point to a sharp pivot from that stance.

Claressa Shields hints at retiring from MMA after 2-1 run in PFL

During a recent media scrum with FightHype and other outlets, Shields addressed what’s next for her in MMA and provided an empty response.

“I don’t know about MMA, I did everything I wanted to do all over there,” Shields said. “I went over there, won two fights, lost a split [decision], there’s not enough time in the day for me to train for MMA…

“Not enough time to train to become a PFL world champion.”

Shields’ honesty provides some clarity on her immediate MMA future. It’s a 180-degree turn from Shields’ faceoff with former boxing foe Savannah Marshall following Marshall’s MMA debut last June at PFL Europe 2.

After Marshall defeated Mirela Vargas in her professional MMA and PFL debut, Shields and Marshall seemed destined for a crossover rematch of their 2022 boxing fight. Shields defeated Marshall in the boxing ring by unanimous decision to hand the UK star her first professional loss.