Abortion rights advocates say a Massachusetts judge's dismissal of drug charges against a woman whose son was born with cocaine in his system will help their fight.

Until last week, a pregnant woman in Massachusetts who abused drugs or alcohol faced the possibility of criminal charges if her abuse harmed her fetus.But in a 19-page decision, a Superior Court judge outlined constitutional privacy rights for pregnant women. In a ruling that could influence other judges in Massachusetts and elsewhere, she said the state could not pursue charges against pregnant women that it did not bring against other people.

"No court has ever reached this constitutional issue before," said Lynn Paltrow, an American Civil Liberties Union lawyer in New York.

The ACLU and several women's groups promised to cite the Massachusetts decision in at least six other cases pending in states including Texas, Illinois and Florida.

"This will appear in every brief in every prosecution nationwide," said Nancy Gertner, a lawyer who represented 20 different groups interested in the Massachusetts case.

The prosecutors in the cases say their goal is to discourage pregnant women from drug abuse and similar ills that would cause them and their fetuses harm.

But Plymouth County Superior Court Judge Suzanne DelVecchio cited alternatives to prosecution of women whose habits hurt their fetuses - such as education and free medical care.

"By imposing criminal sanctions, a woman may turn away from seeking prenatal care for fear of being discovered," she wrote.

In throwing out the case against 24-year-old Josephine Pellegrini, a mother of three, DelVecchio also said that government should not interfere with the "intimate and fundamental bond" between a woman and the fetus she bears.

"This court will not permit the destruction of this relationship by the prosecution," she said.

Pellegrini of Brockton had been indicted by a Plymouth County grand jury in September 1989 on charges of distributing cocaine to a minor and cocaine possession. A drug screening by doctors found cocaine in the urine of her son, Nathan, born July 2, 1989.

A leading opponent of abortion said DelVecchio's decision highlights the need to overturn the landmark Supreme Court decision legalizing abortion.

"I'm sure nobody in the country ever expected Roe vs. Wade meant to protect a woman's right to inflict illegal drugs on an unborn child," said Ruth Pakaluk, president of the Massachusetts Citizens for Life.

"One of the reasons this whole area of law makes no sense is, if it is legal to kill an unborn child, how on earth can it be illegal to inflict a little harm?" she continued. "As long as abortion on demand is the law, all the rest of this is schizophrenic."

Pakaluk and her colleagues argue a fetus is a human being and should enjoy the freedoms and protections of everyone else.

"The protections of a fetus shouldn't be superior or hostile to the interests of a pregnant woman," countered Joyce Cunha, associate director of the abortion rights group MassChoice.

Women's advocates say the fetal rights cases are critical because once a pregnant woman is held liable for some damage to her fetus, the door will be wide open for regulating her every move.

ACLU's Paltrow said states might try to dictate "what she eats, where she works and whether she can change the (cat) litter." (Cat feces sometimes carry a disease organism that can be harmful to fetuses.)

Abortion rights advocates acknowledge DelVecchio's ruling does not carry beyond her county jurisdiction. But with no other written guidance on the subject, it carries unusual weight.

"The absence of any decision like this meant every prosecutor nationwide could decide how to reinterpret common law," Gertner said. "It was anarchy. Every politically ambitious prosecutor could decide this would be his contribution to the drug war."

In Greenville, S.C., this month, a woman who gave birth to a cocaine-addicted baby was sentenced to 10 years in prison after authorities said she repeatedly failed to complete drug programs designed to help her overcome her problems.

On the same day that mother pleaded guilty to charges of child neglect, a Spartanburg County magistrate ruled the state's child neglect law can be applied to an unborn fetus in the case of a woman whose baby boy was born with symptoms of heroin addiction.