Mo. Rev. Stat. § 376.807: Policies not to reduce or deny benefits to persons eligible for medical assistance — deemed primary contract.

1. No contract of medical expense insurance, delivered or issued for delivery, amended or renewed in this state after August 13, 1988, by a self-insured or self-funded plan, prepaid health plan, health maintenance organization plan, health services corporation plan or insurance company licensed to issue policies in this state, shall contain any provision denying or reducing benefits because services are rendered to an insured or dependent who is eligible for or receiving medical assistance pursuant to chapter 208.

2. All such contracts shall be deemed to be the primary coverage of an insured or dependent who is eligible for or receiving medical assistance pursuant to chapter 208.