Despite the unprecedented efforts of the seven Democratic presidential candidates to make an impression on party activists in Iowa, a new Iowa Poll suggests that none of them has made notable progress.

With five months to go, no candidate received as much as 20 percent support of the 316 Iowa Democrats surveyed who indicated they will attend the Feb. 8 caucuses. This was the first Iowa Poll focusing on likely caucus participants. It was published in the Des Moines Register.

Eighteen percent of the Democrats surveyed said Rep. Richard A. Gephardt (Mo.) is their first choice or they are leaning toward him. Massachusetts Gov. Michael S. Dukakis followed with 14 percent and Sen. Paul Simon (Ill.) with 13 percent. The differences in support among the three are well within the poll's 5.5 percent margin of error.

Sen. Joseph R. Biden Jr. (Del.) drew 10 percent, Jesse L. Jackson and former Arizona governor Bruce Babbitt, 9 percent, and Sen. Albert Gore Jr. (Tenn.), 2 percent. Rep. Patricia Schroeder (Colo.), who has not decided whether to run, received 5 percent support.

Only 25 percent of Democrats likely to attend the caucuses said they were firm in their commitment to their first-choice candidate.

Just one Democrat drew strong opposition. When asked which of the candidates they would least likely support, 26 percent of likely caucus-goers named Jackson.