Russian law student Oxana Fedorova won the pageant in May, but was fired Monday after serving just four months of her one-year term.
The head of the Miss Universe Organization said she was fired because she "was unable to fulfill her duties."
Paula Shugart said that Miss Universe is required to spend much of her time traveling around the world. And she said Fedorova couldn't do that.
Shugart said she believes Fedorova's mother had been ill at one point.
When asked about reports that Fedorova was fired because she is married or pregnant, Shugart said, "No, I honestly have no idea where any of that came from."
In an interview with a Russian television network, Fedorova reportedly denied she was fired, saying she gave up the title voluntarily.
She is to be replaced by Panama's Justine Pasek, who is to be crowned by Donald Trump at a news conference Tuesday.