U.S. Republican presidential hopeful Michele Bachmann is suspending her bid for the White House after coming in a distant sixth in the Iowa caucuses, CNN reported on Wednesday.

The U.S. congresswoman's decision to pull out could favour rival Rick Santorum, who narrowly came in second to Mitt Romney in Tuesday's Iowa caucuses.

Santorum, Bachmann and Texas Governor Rick Perry, who is reassessing his campaign, have been courting support from evangelical Christians. If a significant number of evangelicals eventually rally behind Santorum, his long-shot campaign could receive a major boost.

Bachmann cancelled a campaign trip to South Carolina on Wednesday and scheduled a news conference for 11 a.m. EST (4 p.m. British time)

The Iowa-born Bachmann, 55, was once a leading light for evangelical voters in Iowa but garnered only 5 percent of the vote in Tuesday's first voting contest to pick a candidate to challenge Democratic President Barack Obama in 2012.

Those results raised the already colossal odds against Bachmann's bid.

Santorum, a former U.S. senator from Pennsylvania, and Ron Paul, a Texas congressman with libertarian views, garnered a larger percentage of the crucial conservative vote and are now the leading alternatives to front-runner Romney, the former Massachusetts governor, as the candidates prepare for the next voting contest in New Hampshire.

Bachmann shot to the top of polls in August after winning the Ames Straw Poll in Iowa, but later suffered from staff departures and fundraising troubles. By the end of December, her popularity had dwindled in the state.

(Reporting By Harriet McLeod, and Eric Johnson, writing by Ross Colvin; Editing by Vicki Allen)