Is it true your cervix is always blue when your pregnant

Not in the sense you are thinking.

When pregnancy occurs there is a bluish tint to the cervix. This is called Chadwick's Sign.

Not in the sense you are thinking.

When pregnancy occurs there is a bluish tint to the cervix. This is called Chadwick's Sign.

So during a pap a obg would have noticed?

Yes. They would notice Chadwick's Sign.