215 ILCS 165/14
Every subscription certificate issued by a health services plan corporation shall provide for the rendering of health services as therein specified for a period of 12 months from the date of issuance of the subscription certificate subject to compliance with the by-laws and rules and regulations of the corporation by the subscriber. Any such certificate may provide that it shall ordinarily be renewed from year to year unless there has been one month's written notice of termination either by the subscriber or by the corporation. During the first contract year the provisions of the contract may provide that the coverage by the contract may be deferred for not more than two months from date of issue of the contract and may exclude treatment for illness or other conditions requiring service existing at the time of executing the contract.
215 ILCS 165/14