I am pregnant and I want to leave my husband and move out of state to my mother's house. My husband say's I can't since I am pregnant with his child. Is it against the law for me to leave the state my husband live's in with my unborn child?

Since you are married he is the presumed father and has rights. If you leave the state, he can file for divorce before you can establish residency in another state. This means he can be in control. It would be better if you file, get your divorce and request being able to move as part of the divorce.

... Is it against the law for me to leave the state my husband live's in with my unborn child?

No.

You are not your husband's property. And he has no rights with respect to your unborn child until the child is actually born.