Moody's Investors Service said Monday it has placed several Coventry Health Care Inc.'s debt ratings under review for a possible upgrade, citing the company's latest quarterly results and improved 2011 earnings outlook.

Moody's review will focus on Coventry's ability to sustain earnings margins and membership.

"The slow economic recovery, which may continue to pressure membership, and the implementation of minimum medical loss ratio regulations may present some challenges for the company," said Steve Zaharuk, a senior vice president at Moody's.

Still, the company's first-quarter and 2010 results suggest both margins and membership should be strong the rest of this year, the firm concluded.

The Bethesda, Md.-based health insurer reported last month that its profit climbed 13 percent in the first quarter, helped by higher premiums and commercial fully insured enrollment. It also raised its 2011 earnings per share forecast to between $2.65 and $2.85. Analysts expect earnings of $2.97 per share.

Moody's said Coventry's financial profile continues to improve, noting its profit margins increased last year compared with 2009. The company's access to cash from its non-insurance subsidiaries has strengthened its financial flexibility, Moody's added.

Membership in Coventry's commercial and Medicare segments appears to have stabilized, and the company has opportunities to grow its Medicare and specialty businesses, the ratings firm said.

Among the debt Moody's could upgrade are Coventry's senior unsecured debt, senior unsecured credit facility and corporate family debt, all now rated "Ba1," including about $1.6 billion in debt in all.

Moody's also is reviewing ratings on Coventry health care plans HealthAssurance Pennsylvania Inc., HealthAmerica Pennsylvania Inc. and Group Health Plan Inc., which all are now at "Baa1."

Shares in Coventry Health Care ended the regular session up 32 cents to $34.67.