While her colleagues were sworn in yesterday as members of the 97th Congress, Rep. Gladys N. Spellman (D-Md.) lay in her bed at Prince George's General Hospital still unable to speak, move or otherwise indicate that she will someday be able to serve a fourth term.

Because her doctor acknowledges that "it is not likely" that she will ever fully recover, her illness poses a delicate, but largely unspoken, dilemma for political friends and foes over how long she can remain incapacitated without giving up or being stripped of the 5th Congressional District seat to which she was overwhelmingly elected four days after suffering massive heart arrest last October.

For now, neither party seems anxious to deal with the question. Democratic colleagues in the House ignored the absence of the 62-year-old legislator yesterday, and Republicans, wary of appearing ghoulish, discussed Spellman only long enough to decide to do nothing about seeking to have the seat declared vacant.

Although Spellman's staff resolutely refuses to talk about any alternative to recovery by the Democrat and resumption of her duties, the congresswoman's husband, Reuben, said yesterday that if the seat is vacated, there is "a possibility" that he would seek it.

But there is no deadline, he insisted, on when such a decision would be, and "there is no time frame for her recover." One factor on his decision, he said, would be her health, and "no one can predict the speed of her recovery."

Spellman spent much of the day in his wife's office, and watched forlornly on a television set as House Speaker Thomas P. (Tip) O'Neill swore in representatives of the 97th Congress and, a few minutes later, as the light next to his wife's name remained unlit on the first quorum call of the new Congress.

While family and close associates of the stricken representative remain optimistic that she will eventually recover, the medical prognosis is less certain. Michael Schwartz, her cardiologist, said yesterday that after two months of observation and testing, he feels that a complete recovery by the congresswoman is unlikely.

Spellman os no longer in a continuous "sleep-like state" and now appears able to focus her eyes on visitors and television, Schwartz saidm but "she is not fully cognizant when she's awake. She looks at you, she looks at the TV, but how much she understands we don't know. She can't communicate."

Although it is impossible to determine whether Spellman will improve further, Schwartz said he hopes whe will be aided by newly begun speech and physical therapy. According to Spellman's office staff, the representative will be moved out of Prince George's General within the month and into another facility -- possibly Walter Reed Army Medical Center -- for longer-term rehabilitation care.

While the Spellman family this month must focus on the representative's long-term care, Congrss will be forced at the same time to deal with the problems of her continued absence.

"We're going to have to face up to it on the first payday, Jan. 31, because no member can be paid unless he or she has been sworn in," said one House official. Also without that formality, staff cannot be paid unless the House adopts a resolution authorizing payment.

Although Spellman was absent yesterday, three new area representatives were in their seats when House Sergeant-at-Arms Benjamin J. Guthrie gaveled the new House session to order at 12:07 p.m. Democrat Roy Dyson, who defeated Republican Robert E. Bauman in the 1st District of Maryland, and Republicans Stanford E. Parris and Frank R. Wolf, of the 8th and 10th districts of Virginia, respectively, were among 417 House members who answered the first quorum call.

Several of the 18 missing members straggled in later in the day, and a few others were absent because of the flu. By special resolution, the House approved the request of Rep. Jack Edwards (R-Ala.) that he be sworn in yesterday at the federal courthouse in Mobile by a U.S. District Court judge. Edwards underwent surgery Dec. 19 for the removal of a kidney stone and is expected to return to Washington about Jan. 15, an aide said.

When Spellman's aides are asked how long a member can linger without having the seat being declared vacant -- and they contend that "the only people asking are reporters" -- they cite as precedent the case of Rep. Lawrence Lewis of Colorado, who was elected to the 78th Congress, which convened on Jan. 3, 1943, but who did not take the oath of office from Speaker Sam Rayburn until nine months later, on Sept. 14.

Reuben Spellman met last month with both Speaker O'Neill and Maryland Gov. Harry Hughes, and both assured him that they had no plans to pressure him for his wife's resignatuon, according to Edna McClellan, the congresswoman's chief aide.

In lieu of sending holiday greetings to constituents, Reuben Spellman, a retired federal employe, sent letters to several thousand Spellman supporters in Prince George's County in which he pledged to "remain ever sensitive to the political aspects of Gladys' illness and to do nothing that is not in the best interests of her constituents."