Frankly I have had just about as much as I can stand of pro-lifers worshiping the fetus. Most of them only care about it until it's born, anyway. If the patient refuses medical treatment, that's her business and no one else's. If you're a medical practitioner I support your right to passionately and loudly argue at her that this treatment is needed, but that's it.
A pregnant woman shouldn't be allowed because it'll hurt the fetus, who given a choice would probably avoid being hurt. What should be done should be what's best for the fetus, even though the mother should have priority in the choice since the fetus isn't considered an adult. I believe this will benefit the fetus more and avoid future problems, even death if the woman refused.