WASHINGTON (Reuters) - President Barack Obama called a law student on Friday after she was branded a "slut" by right-wing talk show host Rush Limbaugh for her outspoken support of Obama's new policy on contraception.

Sandra Fluke, a student at Georgetown University in Washington has been caught in the middle of a contentious election-year fight between Obama and Republicans over the policy, which requires health insurance plans to cover contraception.

Religious-affiliated organizations, the Roman Catholic Church and social conservatives have protested the policy as an infringement on religious liberty. An effort by Republicans in the Senate to overturn it failed this week.

Fluke has spoken out against the Republican effort and advocated making contraception available to all women, drawing fire from Limbaugh and some other conservative commentators.

"The president called her to thank her for speaking out ... and expressed his disappointment that she had been subjected to these kinds of attacks," White House spokesman Jay Carney told reporters.

Obama's policy, which requires all employers that provide health insurance -- except for houses of worship and churches -- to provide coverage for women's contraceptives, has created a election-year firestorm. Non-employer sponsored health insurance policies would also have to cover them.

Obama subsequently tweaked the policy so that religiously affiliated employers like hospitals, universities and charities would not be required to cover the cost, which would fall instead on insurers. That did not satisfy the Catholic Church, whose official policy rejects the use of artificial contraceptives.

Limbaugh first blasted Fluke on Wednesday. He repeated the charges on Thursday, saying: "Well, what would you call someone who wants us to pay for her to have sex? What would you call that woman? You'd call 'em a slut, a prostitute or whatever," Limbaugh said on Thursday.

Obama spoke with Fluke for several minutes from the Oval Office, Carney said, making clear the president was troubled by the remarks.

"He thinks they were reprehensible, they were disappointing," Carney said. "It is disappointing that those kinds of personal and crude attacks could be leveled against someone like this young law school student, who was simply expressing her opinion on a matter of public policy."

Limbaugh's comments also drew criticism from Republican House of Representatives Speaker John Boehner, whose spokesman said they were "inappropriate."

Fluke told lawmakers recently that female students at Georgetown, the oldest Catholic and Jesuit university in the country, suffered financial hardship because contraception was not covered by their healthcare insurance and in some cases had stopped taking it because it cost too much money.

(Reporting By Alister Bull; Editing by Peter Cooney)