WellPoint Inc reported a higher fourth-quarter profit on Wednesday and said it was taking a "prudent" view of 2013 as the second-largest U.S. health insurer faces industry reform.

WellPoint, which sells private health insurance to businesses and individuals and also provides government insurance for the elderly and the poor, is preparing for a round of changes resulting from the U.S. Affordable Care Act.

Later this year, states and the federal government will begin selling health insurance on exchanges for 2014, and new insurance taxes are on the way. Pressure on prices for medical services is also a concern for insurers.

WellPoint said that given the "fluid and dynamic" market over the next 18 to 24 months, it expected a 2013 net profit of at least $7.60 per share, including the costs of integrating its recent acquisition of smaller competitor Amerigroup.

Analysts on average have been expecting $7.98, according to Thomson Reuters I/B/E/S. It was not immediately clear if the two numbers are comparable.

The company said that fourth-quarter net profit had risen to $464.2 million, or $1.51 per share, helped by an income tax settlement and investment gains.

WellPoint, which included Amerigroup figures in its earnings report for the first time, said it had 36.1 million members as of December 31, up 5.5 percent from a year earlier.

It said it expected membership to drop in 2013 to a range of 35.3 million to 35.5 million.

Excluding the tax settlement, investment gains and other special items, the company said earnings had increased to $1.03 per share from 99 cents a year earlier.

On that basis, analysts on average had been expecting a profit of 95 cents per share, according to Thomson Reuters I/B/E/S.

WellPoint said that lower-than-anticipated medical costs in its private insurance business, stable membership numbers and strong operating cash flow helped earnings during the quarter. It said its fourth-quarter tax rate had been abnormally low because of a settlement with the Internal Revenue Service.

Revenue for the quarter rose to $15.27 billion from $15.18 billion a year earlier.

WellPoint's results followed those of the larger rival UnitedHealth Group Inc , which last week reported a slight drop in net income and said the next two years had the potential for growth and opportunity.

(Reporting by Caroline Humer; Editing by Lisa Von Ahn)