By altering an "a" to an "e" and inserting a few phrases here and there, a special legislative conference committee today worked out a compromise on abortion funding that is expected to reduce the number of Medicaid abortions for indigent women in Maryland.

The abortion compromise, drafted at a four-hour committee session this morning, was adopted by the House of Delegates late this afternoon and approved by the Senate tonight with enactment of the $4.8 billion state budget. Abortion fundings is a small but extremely controversial part of the budget.

Although the compromise language is said to be more restrictive than the current state policy, which funded 5,800 abortions for poor women last year, no one on the six-member conference committee could say to what extend state-funded abortions would be reduced under the new guidelines.

"This is the kind of compromise where no one knows who won or lost," said Del. Timothy Maloney (D-Prince George's), one of three antiabortion legislators on the special panel. "It really is impossible to say now just how great the reduction in abortions will be. It depends on how the new language will be interpreted by the secretary of health and mental hygiene. The ball is clearly in his court."

The abortion policy that the health secretary, Dr. Charles Buck, will have to interpret in processing Medicaid claims is a carefully worded document that, according to both sides, has one key phrase. It allows for state-funded abortions when "it can be ascertained by the physician with a reasonable degree of medical certainty that the continuation of the pregnancy could have an adverse effect on the woman's present or future physical or mental health."

The committee members on both sides of the issue fought over every word in that phrase. By changing "affect" to "effect" the antiabortionists felt they prevented a few abortions. By changing "will" to "could" the proabortionists felt they gave a few more poor women the right to choose an abortion.

"It was like a freshman English class all morning," said one member of the committee. "Every article, every clause, was subject to debate and interpretation."

The abortion-fundung dispute has tormented the General Assembly since the first day of the 1979 session, when antiabortion legislators, backed by an everpresent legion of "prolife" activists, demanded a change in the abortion policy enacted last year. That policy was much too broad for the antiabortionists, who noted that state-funded abortions dropped by only 10 percent in the year since the law as enacted.

The key phrase in the law was one that allowed for state-funded abortions when continuation of the pregancy would be "determental to the health of the mother." According to the antiabortionists, this phrase was so broad, and physicians and state health officials interpreted it so loosely, that the state was actually funding what they called "abortion on demand."

In an effort to make the law more restrictive, the antiabortionists pushed a measure that would allow for state-funded abortions only when the pregnancy would create "severe and long-lasting physical health damage" to the mother. By replacing this phrase for the "detrimental to the health" language, they believed they could reduce the number of state-funded abortions by 90 percent.

The General Assembly could not agree on the issue last month. First the House of Delegates rejected the antiabortion language, with a narrow majority of delegates maintaining that it amounted to discrimination against women unable to pay for their own legal abortions. Then the Senate adopted the restrictive measure, and the dispute was sent to the special conference committee for resolution.

The special committee included Maloney, Sen. Peter Bozick (D-Prince George's) and Sen. Jerome Connell (D-Anne Arundel) on the antiabortion side, with Sen. Rosalie Abrams (D-Baltimore), Del. Lorraine Sheehan (D-Prince George's) and Del. Torrey Brown D-Baltimore) as proponents of the more liberal abortion policy.

After establishing a few ground rules over the weekend, the committee met this morning in Brown's legislative office. The press was barred from the meeting.

The language that the committee hammered out was based on a draft proposal presented by Sen. Connell, who according to several members of the committee served as the driving forcef for the eventual compromise. Although there was apparently little acrimony durign the four-hour session, one member of the committee noted that "there were several times when everyone thought we were headed back to square one."

The compromise seemed more acceptable to the proabortion side than the antiabortion leaders. Maloney said he was "terribly unhappy" with the proposal, but said he accepted the compromise "as the best we could do under difficult circumstances."

A leader of the Maryland Right to Life Action called the compromise " a fraud" that he said would still allow for "abortion as a means of contraception."