Former House Speaker Newt Gingrich leads the Republican presidential field in Iowa one month before the state's first in the nation primary, according to a new Des Moines Register poll.

Gingrich draws 25 percent support from likely Republican caucus-goers, the Register poll found. That is an 18 percentage point jump since the October issue of the same poll.

Rep. Ron Paul (Texas) took second spot in the poll, earning 18 percent support.

Former Massachusetts Gov. Mitt Romney follows close on Paul's heels. The Register measured Romney at 16 percent support. 

The Romney campaign has only recently begun investing in Iowa, where conservatives have not shown strong inclinations toward the Massachussets governor, and Romney picked up the endorsement of the Sioux City Journal on Saturday.

Rep. Michele BachmannMichele Marie BachmannBachmann won't run for Franken's Senate seat because she did not hear a 'call from God' Billboard from ‘God’ tells Michele Bachmann not to run for Senate Pawlenty opts out of Senate run in Minnesota MORE (Minn.) and Herman Cain, who suspended his campaign on Saturday, led the poll's second tier of candidates with 8 percent support. The Register poll was conducted Nov. 27-30, and Cain announced he was reassessing his campaign's future on Nov. 29.

Bachmann was Iowans' choice in the Ames Straw Poll this summer, and Cain took the top spot in October's Register poll.

Texas Gov. Rick Perry and former Sen. Rick Santorum (Pa.) each earned 6 percent support.

Former Utah Gov. Jon Huntsman trailed with only 2 percent.