Mo. Rev. Stat. § 210.730

The court shall possess continuing jurisdiction in proceedings under sections 210.700 to 210.760 and, in the case of children who are continued under foster care, shall review the status of the child whenever it deems necessary or desirable, but at least once every six months. It shall be the goal of the court and the authorized agency in whose custody a child has been placed, that the percentage of children who are in foster care in excess of twenty-four months shall not exceed thirty percent in any fiscal year.