About 100 proabortion demonstrators marched in front of the Supreme Court building last night on the seventh anniversary of the court's historic decision that gave women the right to decide during the first three months of pregnancy whether to bear a child.

Less than 10 blocks away, about 250 people opposed to abortion rallied in the gymnasium of the Gonzaga College High School on North Capitol Street, preparing for today's antiabortion march from the Ellipse to the west lawn of the Capitol. The march starts at noon.

Tens of thousands of abortion opponents are expected to converge on the Capitol to hear speeches and lobby Congress about a complicated issue that has divided communities across the country.

Francine Ardito, 26, a nurse living in Reston, stood shivering last night in front of the Supreme Court building holding a cloth sign that read: "Motherhood by Choice." She is expecting a child in about two weeks. r

"I'm here because I wanted to show that there are people who are for a choice who do like children," Ardito said. "I wanted this pregnancy. Everybody should have a right to chose that."

"I'm a Protestant, my husband is Catholic, and we're both religious people," she said. "The issue is about women having a safe, legal choice whether to have a child. And even if the government has to pay for it [in the case of poor mothers who are prevented by law from using Medicaid funds for abortions] in the end, we will have more to pay if mothers have unwanted children."

At the Gonzaga gymnasium, Nell Bell, from Pensacola, Fla., and her husband Reed joined a sing-along rally against abortion.

"I believe in the right to life for every individual," said Bell, the mother of six. "We're marching because we can not get a voice with our president against abortion."

"I believe that there are alternatives to abortion," Bell said. "We need to be willing to pay to support mothers and their babies if the mothers cannot afford to take care of them. There are plenty of people who are willing to adopt children, but there aren't enough children."

"Marching is new to me, but if that's the only way we can get heard, then I'm willing to do it," she said.

Bus loads of people from around the country -- from Ohio, Kentucky, Tennessee, Texas, South Dakota -- have arrived in Washington for the march, and about 100 of them began a vigil in front of the White House last night that they said they would maintain until the march begins later today.

Many of them describe themselves as deeply religious and to support their views, they come armed with Bible quotations and testimonies from medical authorities that an unborn child is a human being.

The abortion proponents argue that women have a constitutional right to decide what to do with their own body regardless of the views of others.

The 1973 Surprme Court decision, while allowing a woman to determine whether to abort a pregnancy during the first three months, did not permit her to do so after that period unless it would adversely affect her physical or psychological health.

The issue has been further complicated by a congressional measure passed last year that prohibits federal funds from being used in abortions. Abortion proponents say the amendment, in effect, allows middle income and affluent women to have abortions, while keeping abortions out of the reach of the poor.

For months, both sides have been squaring off for an eventual political battle, lobbying members of Congress, working for political candidates who support their views and conributing to campaigns.