Updated

The doctor who got the U.S. Supreme Court to strike down Nebraska's ban on a controversial abortion procedure testified Thursday that a similar federal law is so vague it would outlaw nearly all abortions after the first trimester.

"There are at least 21 different procedures that it covers," Dr. LeRoy Carhart (search) said during a challenge of the Partial-Birth Abortion Ban Act (search), signed last year by President Bush. "There are terms in this act that I do not understand ... and that have many definitions."

The new law has not been enforced because judges in Lincoln, New York and San Francisco agreed to hear evidence in three simultaneous non-jury trials on whether the ban violates the Constitution.

The ban would be the first substantial limitation on abortion since the Supreme Court legalized it 31 years ago in the landmark case Roe v. Wade (search).

The measure bars a procedure doctors call "intact dilation and extraction," or D&X (search). Opponents call it partial-birth abortion. During the procedure, generally performed in the second trimester, a fetus is partially removed from the womb and its skull is punctured.

The Bush administration has argued that the procedure is "inhumane and gruesome" and causes the fetus to suffer pain.

The new law prohibits doctors from committing an "overt act" to kill a partially delivered fetus. But Carhart said that could be interpreted as covering more common procedures, including "dilatation and evacuation."

D&E (search) is the most common method of second-trimester abortion. An estimated 140,000 D&Es take place in the United States annually, compared with an estimated 2,200 to 5,000 D&X procedures.

A total of 1.3 million abortions are performed in the United States each year. Almost 90 percent occur in the first trimester.

"This act covers every D&E that I did," Carhart said. "Everything that I do to cause an abortion is an overt act."

Carhart said at least once a month, an entire fetus is expelled from the mother during a D&E he is performing. "The fetuses are alive at the time of delivery," he said. There is a heartbeat "very frequently."

Carhart earlier brought a challenge that eventually led the Supreme Court in 2000 to overturn Nebraska's ban on D&X abortions. The high court said the Nebraska law and others like it were an "undue burden" on women's rights.

U.S. District Judge Richard Kopf, who is presiding over the trial in Lincoln, also presided over Carhart's challenge to the Nebraska ban.

Under the federal law, doctors can get up to two years in prison.

The issue is expected to reach the U.S. Supreme Court.

In blocking enforcement of the federal ban last year, Kopf cited concerns that the law did not contain an exception for preserving the health of a woman.

Congress declared that "a partial birth abortion is never necessary to preserve the health of a woman" and is "outside the standard of medical care."

On Thursday, meanwhile, the president signed legislation at the White House expanding the legal rights of fetuses. The Unborn Victims of Violence Act (search), which took five years to get through Congress, makes it a crime to harm a fetus during an assault on a pregnant woman.