Insurer Coventry Health Care Inc on Friday posted a 14 percent increase in third-quarter profit, in line with forecasts, but shares fell on a slightly lower-than-expected 2008 profit forecast.

Coventry, whose shares fell 7.3 percent, said net quarterly earnings rose to $168.7 million, or $1.08 per share. That compared with $147.5 million, or 92 cents per share, a year earlier.

Analysts, on average, expected $1.08 per share, according to Reuters Estimates.

Revenue rose 32 percent to $2.52 billion, helped in part by two acquisitions made in the past year and rising membership in its Medicare plans for the elderly.

Membership was 4.67 million at the end of the quarter, up about 560,000 members from a year ago. Much of that growth has come from new additions to its Medicare plans for the elderly, including 200,000 in its full-service Medicare Advantage plans.

Coventry projected full-year earnings of $3.97 to $3.98 per share, up about 15 percent over 2006.

It forecast 2008 earnings per share of $4.42 to $4.58, up 11 percent to 15 percent over its 2007 expectations.

Goldman Sachs analyst Matthew Borsch said the company's 2008 profit forecast was below his own projection of $4.65 per share.

We would expect shares to see some downward pressure ... given the company's first-time guidance, Borsch said in a research report.

Analysts polled by Reuters Estimates, on average, had expected 2007 earnings of $4.01 and 2008 earnings of $4.58.

Coventry was down $4.48 to $57.27 in morning trading on the New York Stock Exchange.

(Reporting by Lewis Krauskopf and Ransdell Pierson)