Seven women ended a controversial 37-day fast for the Equal Rights Amendment yesterday after the Illinois House rejected the proposed amendment for the seventh time.

Toasting "the new era of women" with champagne glasses filled with grape juice, the women announced they were giving up the fast at a Springfield, Ill., news conference.

The women conceded the vote in the Illinois House ended all hopes that the amendment could be passed before its June 30 deadline. But they called the fast a success.

"We feel as if we have personally been successful," said a skeleton-thin Sonia Johnson, the Sterling, Va., leader of the group. "Perhaps we have lost a battle, but we know we are going to win the war."

Sister Maureen Fiedler of Mt. Rainier, Md., said, "We demonstrated that seven very ordinary women can do extraordinary things. We know the fast has increased a sense of unity and power among women around the country."

The fast ended as congressional supporters of the ERA vowed to reintroduce a new version of the amendment in the House and Senate next month and start the ERA fight anew.

Rep. Patricia Schroeder (D-Colo.) said a new ERA campaign would begin July 14, the day Congress returns from its Fourth of July recess, with a massive news conference on the Capitol steps.

Schroeder said she hopes to have 218 amendment cosponsors in the House by then. A Senate version, circulated by Sens. Paul E. Tsongas (D-Mass.) and Bob Packwood (R-Ore.), already has 38 cosponsors.

"The fact that debate on the ERA has been so lively down to the wire proves that the amendment and the issue is far from its deathbed," Schroeder said on the House floor.

The ERA, first passed by Congress in 1972, has been ratified by 35 states, three short of the 38 needed for it to become a part of the Constitution. But it has not passed in a single state legislature since a controversial vote in 1978 extended the normal seven-year ratification deadline three years to June 30, 1982.

For the process to start over, the amendment would have to be approved by a two-thirds vote in the House and Senate, a prospect some observers say is unlikely given the current conservative makeup of Congress. It would then have to be ratified by 38 states within the following seven years.

The Illinois fast is the most dramatic of a series of last ditch efforts mounted in behalf of the amendment in four states this year--Oklahoma, North Carolina, Florida and Illinois.

The fast began May 18. Since then, the women have lost more than 30 pounds each and the amendment has gone down to defeat in North Carolina on June 4, in Florida on Monday and in Illinois.

Six of the fasters, dressed in white with purple sashes, sat in the gallery of the Illinois House Tuesday night as the amendment fell five votes short of the three-fifths majority needed for passage, 103 to 72. The seventh, Mary Ann Beall of Falls Church, Va., was hospitalized with a collapsed lung.

The measure can still be called up for another vote before the session ends next week, but its chances of passage are poor.

After the vote, the fasters went to a religious service at Springfield's First Presbyterian Church, Abraham Lincoln's old home church. Later, they met in their motel rooms and decided unanimously to end the fast.

"Basically, we thought the fast had achieved its purpose," Fiedler said in an interview yesterday. "We're astute people. We looked at what had happened in North Carolina, Florida and Illinois and decided chances of ratification looked almost nil. To continue would have been futile."

The fasters, who lived on a water-only diet, began drinking fruit juices and eating light foods yesterday. Johnson, Fiedler, Mary Barnes and Shirley Wallace plan to come to Washington today.

Zoe Ann Ananda and Dina Bachelor will return to their homes in California while Beall remains hospitalized in Springfield.