TOPEKA — Coventry Health Care officials have signed an agreement to buy Children’s Mercy Family Health Partners, a health plan that provides services to children in the Kansas HealthWave program.

Children's Mercy covers about 155,000 HealthWave enrollees. HealthWave includes children in the Medicaid and Children's Health Insurance Program.

Coventry also will acquire the Children's Mercy Medicaid business in Missouri, where 55,000 people are covered by the plan.

“This transaction will expand our Medicaid operations while strengthening Coventry’s presence in the Kansas and Missouri markets,” said Coventry Chief Executive Allen F. Wise in a prepared statement.

Coventry officials said the deal will leave the company serving nearly 900,000 Medicaid enrollees across 10 states.

Officials said the deal is expected to close in the first quarter of 2012 subject to regulatory and other approvals.

Coventry, based in Bethesda, Md., is a national managed care company.

The administration of Kansas Gov. Sam Brownback is preparing a plan to reform the state's Medicaid program and officials have said the changes will include greater use of managed care.