This is a Christian school, and every school has a handbook that is handed out every year, to teachers. Among the many requirements is a "Morality Clause". This means, no drunken orgies, no drug use, don't molest students at home, do not be seen by students going into local bars, drinking in public, swearing in public - and many other items.
She knew she was in violation of the school policy - now seems shocked to see that the policy is being enforced. There are other schools with lower standards out there; but is seems pretty hypocritical to tell young teenage girls not to have sex, or to use birth control - then have an unwed and pregnant teacher as a role model.
You are absolutely correct. All the whiners on this thread can go break their contracts and see if they get fired or not.
And children will know that Teacher screwed around without being married and everyone is fine with it. So they will assume they can do the same.