Stephan Bonnar -- Planning UFC 153 Escape ... In Case of Baby Emergency

Win or lose, UFC badass Stephan Bonnar is hauling ass back to the U.S. following his bout against Anderson Silva at UFC 153 -- and TMZ has learned, it's all because his pregnant wife's on the verge of a baby-splosion.

Stephan's wife Andrea tells TMZ, she's due to give birth at the end of the month -- but on the off chance she pops early, Stephan wants to be by her side.

UFC 153 is taking place this weekend in Rio de Janeiro -- so Andrea tells us, Stephan plans to hop a plane as soon as he can after his fight against Silva ... and fly straight back to his wife in Vegas.

But Stephan's not just taking any old plane -- we're told UFC honcho Dana White has offered Stephan the use of his private jet to get him back to Sin City as soon as humanly possible.

We're told Stephan immediately took Dana up on his offer -- but he still has a contingency plan if all else fails ... Skype.