Donald Trump's relationship with Nancy O'Dell was bumpy ... as in he wanted to fire her from the Miss USA Pageant because he felt she was too pregnant to host ... that's what TMZ reported back in 2007.

We posted a story on February 22, 2007, citing a source who told us Trump wanted to drop O'Dell from the show because he didn't want a pregnant woman hosting. NBC overruled him and Trump had no comment on our story.

As you know ... Trump talked to Billy Bush on an "Access Hollywood" bus back in 2005 -- not realizing they were being recorded -- about how O'Dell shut the mogul down when he wanted to have sex with her.