Mont. Code Ann. § 33-22-1901

The provisions of this part apply to all health benefit plans offered to persons who receive health care services in this state. The purpose of this part is to ensure that obstetricians and gynecologists may be participating primary care physicians under health benefit plans offered to patients who receive health care services in this state and that persons covered by health benefit plans have direct access to the services of a participating obstetrician or gynecologist of their choice.