You are worried about him taking the baby away, and yet, you are thinking of not putting him on the birth certificate and moving out of state, yet you don't think he should be feeling that YOU are taking his baby away? Regardless of the reasons that you are moving, OF COURSE he's going to feel like you are trying to take his child from him, wouldn't you feel the same if the shoe was on the other foot?
As another poster mentioned...from a legal standpoint, moving out of state isn't going to be as big of a deal as it would once the child is born. However, it can certainly still factor into legal considerations assuming that he does take this to court. And, being in another state from him is likely to make court proceedings more difficult overall. You might want to check around to see how things are handled if he files for visitation where you are now, but you live out of state-are you going to end up having to travel for court? Also, if he has health issues right now, how much of an option is it for him, really, to up and move with you....and how is the court going to view your leaving while pg in light of those health issues?
I am not saying to stay in the state for him, it could still be that moving is what's best for you and the baby. I am saying that you need to consider all those angles before you move. I think you do need a lawyer ASAP, so that you can discuss all of that stuff and how the laws regarding paternity and visitation and how things are viewed in court in your area to help you figure out how best to proceed.
Unfortunately, once you make a child with someone, you are tied to that person, in SOME fashion for at least the next 18 years. Even if he truely takes off and you never actually see or hear from that person again and you never get child support or have to deal with visitation or any of that, there's the child's thoughts to consider. It's natural for the child to want to know where the father is, why he never sees him, etc etc. And it's certainly not right to lie and say you don't know when you do, so you are still stuck with that tie to that person.