Three insurance companies are newly formed, so comparisons with past rates weren't possible.

CareFirst and other insurers said that they needed to charge more because it would be costlier to cover the sicker people who will come on the rolls. Under reform, insurers will no longer be able to deny coverage to people with pre-existing conditions, a practice some have said has helped keep costs down.

Chester "Chet" Burrell, CareFirst's CEO, was not available for comment Friday, but he has argued that it is hard to predict the costs the company would face because nobody knows how many people will sign up for coverage. The insurer took that into consideration in its request.

Advocates of reform have argued that ultimately costs should go down as more people are required to buy insurance.

"You'll spend more on the premiums, but you'll spend less out of pocket," said Brad Herring, associate professor of health economics at the Johns Hopkins University.

Health Secretary Joshua M. Sharfstein said he thought Goldstein struck a good balance between making sure consumers aren't gouged and taking into consideration increased costs insurers will face.

"Her review was both thoughtful and thorough and her actions will help protect consumers," Sharfstein said.

An analysis of the rates by Maryland Health Connection found that Maryland residents will pay premiums that are among the lowest of 12 states that have passed or proposed insurance rates for their exchanges.

In New York, a 50-year-old resident will pay about $319 a month for a Silver, or midlevel plan, while a Maryland resident will pay $260 to $269 for a similar plan, or about 18 percent less, the report said.

The Maryland Health Benefit Exchange, which runs Maryland Health Connection, will now begin a certification process to make sure plans sold on the state exchange meet requirements of health reform.">