a WordPress rating system

I have two female cats in my house and both are pregnant. They were a mercy adoption kinda thing. So I’m pretty sure that they are on different “levels” of their pregnancy and am wondering, how long to cats stay pregnant and what signs do i need to look for when the go into labor? I’ve never had a cat around when it has kittens, so I’m kinda at a loss right now. I’ve always raised dogs.