California Code, Welfare and Institutions Code - WIC § 15847.5

(a) It shall constitute an unfair labor practice contrary to public policy and enforceable under Section 95 of the Labor Code for any employer to change the employee-employer share-of-cost ratio or to make any other modification of maternity care coverage for employees or employees' dependents that results in the enrollment of the employees or employees' dependents in the program established pursuant to this chapter.

(b) This section shall become operative on July 1, 2014.