After being raped by three men on a Georgia back road, a woman, alone and without money, tried unsuccessfully to obtain an abortion. It was after her traumatic experience in the summer of 1969 that she launched a lawsuit, which eventually led to the Supreme Court's decision legalizing abortion, one of the court's most controversial rulings.

Twelve years ago this week, the Supreme Court voted 7 to 2 that a woman has a constitutional right to abortion.

Many times since that ruling in the case of Roe v. Wade, the legal questions surrounding abortion have been raised again before the Supreme Court.

Nevertheless, the right to abortion today is essentially unchanged since the 1973 decision.

While the court has tinkered with laws affecting abortion -- allowing states to impose funding restrictions, for example -- it has consistently upheld its original holding that most abortions are legal.

"It's no different than it was after Roe v. Wade," said Nellie Gray. president of the March for Life, a national group that is organizing a rally Tuesday on the anniversary of the decision.

She said subsequent rulings that "nibble away" at the original ruling are not altogether satisfactory to abortion foes. "The whole decision must be overturned, because Roe v. Wade said that the preborn are not persons."

Abortion opponents, however, have viewed as moderate victories Supreme Court decisions allowing states to cut off public funding for abortion.

Abortion supporters see the power to deny public funding as a serious problem, but they are generally heartened by the court's consistent refusal to go back on its Roe v. Wade ruling.

"I think people are pleased, given the height of political feeling [on the abortion issue] that the Supreme Court hasn't significantly restricted the private right to abortion," said Jean Marshall Crawford, a member of the board of directors for the National Organization for Women.

In the 50-page Roe v. Wade opinion, the court ruled that during the first three months of pregnancy, a woman's right to privacy protects from state interference her right to obtain an abortion.

During the second three months, states have more right to regulate abortion under the ruling, but only to protect the woman's health.

In the final stages of pregnancy, a state may regulate and even ban abortion, unless the life or health of the woman is threatened.

The central ruling in Roe v. Wade has been challenged only once, in a 1983 case involving an Akron, Ohio, law that imposed regulations on first-trimester abortions.

That law, substantially overturned by the court, imposed a 24-hour waiting period before an abortion could be performed and required physicians to deliver a detailed and anatomical description of the fetus. Doctors were also required to tell patients that the fetus is a "human life from the moment of conception."

In another 1983 decision, the court overturned a Missouri law requiring that second-trimester abortions be performed in a hospital. In both decisions, the opinions reaffirmed the court's commitment to the Roe v. Wade ruling.

Cases less challenging to the basic abortion right but nevertheless affecting circumstances under which abortions can be obtained have appeared on the Supreme Court docket with regularity during the past dozen years. It is in some of these cases that the court has narrowed its original broad protection for women seeking abortions.

In 1977, for example, the court approved the right of states to deny funds for elective abortions for poor women.

And in 1980, the justices allowed a similar ban on use of federal Medicaid funds for abortion. Also in 1980, the court upheld a Utah law that requires notification of parents of "unemancipated" teen-agers before an abortion is performed.