Right-to-life activists are conducting a poll to find the strongest potential antiabortion congressional candidates in the Prince George's County district of ailing Rep. Gladys N. Spellman.

Spellman was reelected to a fourth term this month but has been semicomatose since suffering heart arrest on Oct. 31.. Although her family and supporters maintain that the 62-year-old Democrat could still serve in Congress, the right-to-life groups have hired a Virginia polling firm to test the potential support in her district for a wide range of Democratic and Republican candidates, in the event of a special election.

"We do look ghoulish I'm afraid," said Joe Barnett, head of the national Life Political Action Committee and a board member of the Maryland Right to Life PAC, which are helping to sponsor the $3,000 poll. "But we decided to do the 5th District because we knew we were going to be inundated in February with [candidates] saying, 'I can do it. I can do it.'"

Spellman was felled at a Halloween campaign appearance and has been in a "sleep-like state" since that time, with doctors expressing grave concerns about her neurological condition. Because she has failed to emerge from her semicoma after nearly a month,, a perception has developed in Prince George's political circles that the popular Democrat will be forced to vacate her seat. If that occurs, special primary and general elections would be held.

The poll, which is being conducted by telephone this week, asks registered voters their feelings about such potential candidates as Republican John Burcham, and Democrats Steny H. Hoyer, former State Senate president; Council member Francis B. Francois; State Sen. Tommie Broadwater; Winfield M. Kelly Jr., former county executive;, Lt. Gov. Samuel Bogley, and State Sen. Edward T. Conroy, who unsuccessfully challenged Republican U.S. Sen. Charles McC. Mathias on Nov. 4.

Most, but not all, of the candidates included in the poll are opposed to abortion. But the survey has partisan overtones, as well. Voters are asked who they would favor in a series of matchups between Burcham, who twice has been the GOP choice for the seat, and the most prominent Democrats.

The poll also seeks to identify for whom antiabortion and Catholic citizens voted in the recent presidential election, and how they rated the importance of various national issues, ranging from national defense to federal funding of abortions.

"It's a tracking poll for us, more directed at 1982 than at a special election," said Barrett. "We're looking for the candidates who have the broadest base of support, and what a prolife candidate can reasonably expect in certain areas."

Barrett said the right-to-life groups had agreed to commission similar polls in the 4th Congressional District of Republican Rep. Marjorie Holt and in Baltimore County, but decided to do the Prince George's poll first because of the possibility of a special election.

"Marjorie Holt is being considered for Undersecretary of Defense, and we've got people down there running already," said Barrett. "So we've got the same situation there."

Most of the politicians included in the poll professed surprise yesterday that such activity already was under way.

"I haven't the foggiest idea what it's about," said Burcham. "I haven't felt it appropriate under the circumstances to do anything at all except hope that Gladys will recover."

Del. Timothy Maloney, a prolife leader whose father, Walter H. (Mike) Maloney, is included in the survey, said, "This is premature and dumb. There is a time to do polls and this is not it."

At Spellman's Capital Hill office yesterday, spokesman Art Jaeger said he had not heard about the poll until contacted by reporters. "If a poll is being done, it is not totally unexpected, but it's certainly unfortunate," he added.