Missouri failed in the Supreme Court yesterday to preserve an unusual deterrent to abortion; a law requiring any physician consulted by a woman seeking an abortion to warn her that if he fails, the infant that may be born will become a ward of the state.

Seven of the justices declined to review a ruling by the 8th U.S. Circuit Court of Appeals that the requirement is unconstitutional, partly because it invades "a fundamental... right of personal priacy." Justices Byron R. White and William H. Rehnquist wanted to hear argument in the case.

The law provided criminal penalties for physicians who violated it. The warning applied even to first-trimester abortions, although Missouri conceded that a live birth has "never" resulted from a 12-week pregnancy.

Missouri adopted the requirement in 1974, a year after the high court ruled that a woman in the first trimester has a constitutional right to have an abortion free of state interference.

In a South Carolina case, the court revived the possibility of a prosecution -- for criminal abortion and murder -- of a physician who performed a 25th-week abortion that resulted in the birth of an enfeebled infant. The infant was moved at once to an intensive-care unit where it survived 20 days and then died.

Prosecutor James C. Anders obtained indictments of the doctor Jesse J. Floyd of Columbia, S.C. Anders later admitted that he had acted on the basis of his misreading of an accurate Newsweek article on the 1973 abortion decision; on a summary prepared by a freshman law student of that same opinion, and on a state law whose draftsman had misinterpreted what the opinion said about viability.

It said that viability "is usually placed at about seven months (28 weeks)," but may occur earlier, and is a matter for medical judgement. Once it occurs, however, that state is free to assert its interest in protecting life.

A day before Anders announced the indictments, which are still pending, a federal judge granted Floyd's petition to block them on the ground that there was no possibility of obtaining a constitutionally binding conviction. The 4th U.S. Circuit Court of Appeals, saying that Anders hadn't proceeded "in good faith," affirmed.

The state sought Supreme Court review, saying that the appeals court ruling "permits the destruction of fetuses which... are viable and the proper subject of compelling state interest."

Yesterday, with only Justice Potter Stewart dissenting, the high court nullified the ruling and suggested that the federal judge stay out of the case until further action by the state.

The court did this with a brief, unsigned opinion saying that the federal judge, in blocking the prosecution, may have acted "on the basis of an erroneous concept of 'viability,' which refers to potential, rather than actual, survival of the fetus."