Telling her how you think she's doing it all wrong will only place her further on the defensive, might even compound her issue. I don't think it will give you the peace of mind that you seek. Her reaction will probably only make your blood boil more.
My partner, when 5 months pregnant continued to have issues. I remember trying to explain to her that she needed to be concerned about the child, that some people can't even get pregnant. I tried explaining to her that she needed to get her act together, if not for herself but for the baby in her belly.
All she gave a sh*t about was the drugs she was addicted to.
She dissapeared on me and 4 months later my first daughter was born, heavily addicted to crack.
I say nay. Don't bother trying to make her see your reason.