Abortion rights advocates said today they fear that a new Missouri law criminalizing one type of late-term abortion by terming it "infanticide" will be the prototype for a nationwide effort to get around federal court injunctions against late-term abortion bans in other states.

Their fears appeared at least partly founded when Missouri state Sen. Ted House (D) said that since last Thursday night, when the bill outlawing what abortion opponents call "partial-birth" abortions briefly went into effect, his office has heard from legislators in a half-dozen states where the procedure had been banned and the bans were blocked in court.

House, one of the bill's sponsors, did not name the states, but said, "I've had numerous requests for the bill and there obviously is widespread interest." He said he assumed that the interest stemmed from Missouri's unique approach of not defining the procedure in terms of abortion, but instead prohibiting the killing of an infant by any overt act performed when it is born or partially born. Such an act constitutes the felony crime of infanticide under the new law.

"It draws the line between infanticide and abortion. This approach has never been litigated," House said.

The Infants' Protection Act was passed by the Missouri legislature in May, but vetoed by Gov. Mel Carnahan (D). Last Thursday night, the state Senate voted to override the veto and the law briefly went into effect. But on Friday, Planned Parenthood took the issue to federal court, and a temporary injunction against enforcement of the law was issued by midday.

The law defines a partially born infant as one whose head is outside the mother in a cephalic separation or its navel is visible in a breech delivery. In a partial-birth abortion, a pregnant women's cervix is dilated and after the fetus has partially emerged it is killed by inserting a suction tube into its skull and removing the contents.

Including Missouri, 30 states have passed partial-birth abortion bans, and in 21 of them the bans have faced legal challenges. In 18 states, federal courts have blocked them with either permanent injunctions or temporary restraining orders; in one an injunction was stayed pending an appeal, and in two others enforcement of the laws has been limited by federal court order or the state attorney general.

Many of the state bans were struck down because the courts found that their definitions of partial-birth abortion were so broadly drawn that they challenged the legality of abortions clearly protected by the Supreme Court in Roe v. Wade.

Kate Michelman, president of the Washington-based National Abortion and Reproductive Rights Action League, said the state legislators who have expressed interest in copying Missouri's law are "grasping at any version they think might be able to make its way down the judicial pipeline to overturning Roe v. Wade."

"It's another generation in their relentless attempts to criminalize abortion," Michelman said. "I'm not surprised there's so much interest in it in other legislatures, because those who oppose abortion are determined to find a way to overturn Roe v. Wade."

Lou C. DeFeo, executive director of the Missouri Catholic Conference, an agency of the Roman Catholic Diocese of Missouri, dismissed criticism of the new law as an attempt to generate "hysteria" over a measure that does nothing but "draw the line between infanticide and legal abortion."

All of the other states approached the issue by trying to regulate an abortion procedure, and the courts held the definitions to be too vague, said DeFeo, who wrote the first draft of the law.

"We learned from that experience, and in very anatomically precise language we drew the red line where a child is born. If the navel is exposed, if the head is exposed, we have a person, and you can't purposefully kill the baby. It's as simple as that," DeFeo said.

He said the reason the bill was necessary is that "we don't know the point at which the child has the protection of the law during birth and we should know that." DeFeo also said that if he and the state legislators had drafted a bill that attempted to regulate abortion in such a way that would preclude partial-birth procedures, it would be held unconstitutional.

But critics of the Missouri law say it is even more broadly drawn than partial-birth bans enacted in other states, and that the use of the emotive term "infanticide" will put doctors at abortion clinics at increased risk of violence by antiabortion extremists.

"It is an open invitation to violence," said Janet Benshoof, president of the New York-based Center for Reproductive Law and Policy, who has served as counsel for many of the partial-birth lawsuits. "This is the first time there's been a green light for antiabortion terrorists to claim that their acts of violence were justifiable."

Abortion providers here said that the veto override Thursday night had an immediate "chilling effect" on their patients, who had to wait in clinics Friday morning to see whether the law would be blocked in court.

Paula Gianino, president of Planned Parenthood of the St. Louis Region Inc., which operates an abortion clinic here, said all procedures were suspended for the half day before the court blocked the ban. She said pregnant women were crying because they feared a prolonged shutdown like the one in Wisconsin last year before that state's partial-birth abortion ban was blocked by a federal court order.

"It had an extraordinarily chilling effect," said Gianino, "because I don't think any of them thought this would happen in Missouri." She said no partial-birth abortions were scheduled--and, indeed, Planned Parenthood says that it has found no record of the procedure ever having been performed in the state. But Gianino said the clinic briefly suspended all operations because it was felt staff members might be held criminally liable if they performed any kind of abortion.

Gianino said the clinic had resumed normal operations since the injunction was issued, but added, "The uncertainty is still there, because it's not a given that the court will permanently prevent the law from going into effect."

U.S. District Judge Scott Wright today extended his temporary restraining order until March 27, when a trial is scheduled on Planned Parenthood's request for a permanent injunction.

House dismissed as "smoke screens" and "scare tactics" the abortion rights advocates' assertions that the Missouri law is so broad that it would apply to cases in which a cancerous uterus is removed with a live fetus inside it.

"Read the bill, it's clear. It requires an overt act with the purpose of causing the death of a baby after it's born," House said. "This bill isn't even about abortion, because abortion is done inside the mother."

CAPTION: Missouri state Sen. Ted House: "I've had numerous requests for the bill."