Ronda Rousey has described a ‘life-changing’ diagnosis that prompted her grand return to MMA.The 39-year-old and first female UFC champion is set to end her nearly 10-year hiatus from mixed martial arts on May 16.Rousey vs Carano headlines a stacked MVP MMA card, which also features Francis Ngannou and Nate DiazGettyRousey faces Gina Carano under the banner of Jake Paul and Nakisa Bidarian’s Most Valuable Promotions as the headliner of Netflix’s inaugural MMA event.She is returning to competition for the first time since December 2016, when Amanda Nunes knocked her out in 48 seconds, 13 months after suffering her first MMA defeat, also via KO, from Holly Holm.Rousey’s ‘concussion’ symptoms diagnosedAt the time, Rousey was suffering from ‘neurological issues,’ and these compounded her mental health struggles and ‘self-destructive’ thoughts, which she recalled in great detail in her memoir, Our Fight.It all eventually led to Rousey moving away from MMA, having stated multiple times that she retired mostly because of repeated concussions.However, speaking to The Independent this week, ‘Rowdy’ has revealed her symptoms were actually related to migraines, rather than progressive CTE. It’s great news for Rousey, who will have to pass extensive medical tests alongside fellow women’s MMA trailblazer Carano for their featherweight contest in Inglewood, California.“I thought these were concussion symptoms, because the more concussions I got, the easier it was for me to get these symptoms,” Rousey said, admitting she used to get hit and lose chunks of vision.“So after my first loss, I was like, ‘F***, it’s finally caught up to me. I’m never gonna be able to compete at the highest level again.’“I just felt like I was forced to retire; there was no way I could safely compete at the highest level anymore. “But it was also the toxicity of my training camp. The process wasn’t fun anymore, and I was just so over it.Rousey was knocked out twice in her final UFC fightsGetty Images - Getty“Everything was so result-oriented, and I wanted to enjoy the everyday and not just the possible results.”Rousey: Brain tests were ‘life-changing’Rousey said the fear of her symptoms led her to pro wrestling, having officially joined the WWE in early 2018.But, with the help of UFC president Dana White, concerns around her brain health have now been cleared up.“Fortunately, because Dana sent me to the Cleveland Clinic, we got a diagnosis for what was actually going on with me,” Rousey concluded.“They think it’s actually migraines, and they got me on preventative migraine medication, and we’ve been able to test with sparring and see that it works. “It’s been absolutely life-changing for me.”Rousey discovered that her symptoms were actually related to migraines, rather than concussions or CTEGettyRousey tried to make her MMA comeback through the UFC, but negotiations with White never materialised.She has been at the epicentre of a war of words with her old promotion ahead of her comeback on May 16.Also on the Netflix card, both Francis Ngannou and Nate Diaz are making returns to MMA after lengthy spells out.UFC ScheduleFor all the upcoming fights and results this year, check out talkSPORT.com’s UFC schedule.