It has been known to happen, but is highly risky and not all babies survive because their little lungs, skin, etc., are not developed enough. Still, miracles never cease.
Yes, its happened and its not a good think. The baby most likely will have medical issue's or could be lost. The baby won't survive.
Five months is 20 weeks. I know of a baby that survived at 22 weeks, but generally the doctors will not even put a baby born earlier than 24 weeks on life support. The chances of a baby born at 20 weeks surviving are almost nil.
