Both "The 2 women sleep..." and "2 women sleep" are ok, and accepted.
The meaning of the 2 sentences are not the same.
The 2 women... implies you have already talked previously about them, in another sentence. 2 women sleep... is the way you relate something you didn't talked about before, it's the common way to say it.
Why is it duae instead of duo? Numbers never have to agree with attributed noun in other languages and honestly makes perfect sense why they don't. So why here?
In Spanish number one agrees with the noun (uno / una). So it happens in other languages too.