(AP) — UnitedHealth Group Inc.’s first-quarter net income rose 3 percent as enrollment and revenue gains countered an increase in operating costs, and the health insurer raised its 2012 earnings forecast.

The Minnetonka, Minn., company said Thursday it earned $1.39 billion, or $1.31 per share, in the three months that ended March 31. That’s up from $1.35 billion, or $1.22 per share, in the same quarter last year. Revenue grew 7 percent to $27.28 billion.

READ MORE: Next Weather: Slightly-Warmer Wednesday, Severe Storms Possible Thursday

The performance topped Wall Street expectations. Analysts surveyed by FactSet forecast, on average, earnings of $1.16 per share on $27.01 billion in revenue.

UnitedHealth routinely trumps Wall Street quarterly expectations by a wide margin, but the company’s first-quarter earnings growth wasn’t what analysts and investors are accustomed to. Last year, for instance, first-quarter net income advanced 13 percent compared to the previous year.

The insurer reported a relatively solid quarter and guidance increase this year, but it also has produced “very strong first quarters in recent years and expectations may be high,” Leerink Swann analyst Jason Gurda said in a research note.

UnitedHealth is the largest health insurer and the first to report earnings every quarter. Health insurance is its biggest business, but it also operates segments that sell wellness programs and information services.

The company has touted its Optum business, which provides health management, technology outsourcing and pharmacy benefits, as an important source of future growth. Revenue from that segment climbed 8 percent to $7.3 billion in the first quarter.

The insurer said enrollment for its UnitedHealthcare insurance business climbed 3 percent to 35.6 million people compared with the end of 2011.

READ MORE: VeeCon To Brings Thousands, Including Some Big Celebs, To Downtown Minneapolis

UnitedHealth recorded a $530 million gain in the quarter because claims leftover from previous quarters came in lower than the insurer expected. That compares to a $440 million gain in last year’s quarter.

It also saw another gain as it updated estimates for the premium rebates it is required to pay under the health care overhaul. Insurers are essentially required to spend a minimum percentage of the premiums they collect on medical claims or issue rebates to consumers under a provision of the overhaul that started last year.

Total operating costs climbed as the amount UnitedHealth paid in claims rose 6.5 percent to $19.94 billion.

UnitedHealth now expects 2012 earnings to range between $4.80 and $4.95 per share. That’s up from a previous forecast for earnings between $4.60 and $4.80 per share. It still expects revenue to fall between $109 billion and $110 billion.

Analysts forecast earnings of $4.83 per share on $109.1 billion in revenue.

UnitedHealth’s performance is often seen as a bellwether for the managed care sector. WellPoint Inc., the second largest insurer, reports results April 25, and Aetna Inc. follows on April 26. Humana Inc. reports its earnings April 30, and Cigna Corp. is scheduled for May 3.

Shares of UnitedHealth climbed 68 cents to $58 before markets opened Thursday.

MORE NEWS: What Are The Benefits Of Ramp Meters?

(© Copyright 2012 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)