There is probably nothing more heart-rending and tragic for parents than to give birth to a severely deformed baby. In two recent cases, that tragedy has been compounded by the fact that modern medicine can save the lives of infants who in an earlier time would have died, and their parents have had to decide whether to have corrective surgery performed. A case involving a Down's syndrome baby in Indiana and another case involving a spina bifida baby in Illinois have now placed the private anguish of two families under public scrutiny and touched off a furor in the right-to-life movement.

The Reagan administration has threatened to withhold federal funds from hospitals that deny food or treatment to handicapped newborns. Some people see this as a symbolic gesture to the antiabortion lobby, and some see it as dangerous interference in a traditional doctor-patient relationship, and still others--namely, the handicapped lobby--see it as a bitter irony that this is all the administration has done so far for the handicapped.

Threatening to withhold money is certainly a heavy-handed approach, at least by itself, to a complex problem that in the past was handled quietly by the doctors and parents involved. Now, however, right-to-life advocates working in hospitals are drawing attention to these situations. Babies who have the most limited opportunity at life, and may face great pain, are becoming the objects of court suits and investigations, their parents the victims of everything ranging from misplaced good intentions to outrageous harassment.Since the administration has chosen to get involved in this, it ought to get involved constructively, facing four-square the awful financial and emotional burden it is placing on parents by pressuring hospitals to keep these infants alive. It ought to face, too, the fact that there are tremendous ethical and moral questions, compounded by widespread ignorance, that guidelines could help resolve. Just as the medical community has looked hard at the issue of prolonging adult life with extraordinary measures, so should there be a discussion of the kinds of questions posed by these infants. It is not a matter to be left up to solely to the courts or to the whim of regulators in the Health and Human Services Department.

Marilyn Trainer, the mother of a 15-year-old Down's syndrome child, has counseled numerous parents who have given birth to such children and has a better idea than most of us of what they face. "I think taking the decision away from parents and hospitals is really dangerous," she says, "but at the same time when this first happens parents may not be in the position to excercise the best judgment.

"They are mourning. The baby they expected didn't come. Instead they are left with this enormous problem." They, and their doctors, may also not be well-informed about what infant stimulation and the right to public education have done for retarded children. "Forty years ago the kids with Down's syndrome were called mongoloid idiots and sent away to state institutions for the feeble-minded," says Trainer. "Now more and more parents are keeping their Down's syndrome babies at home. There is more and more enlightenment concerning Down's syndrome." Her son Ben can read and do simple math. "The difference is like night and day between the kids who've had opportunities and those who haven't.

"If there is going to be a law that says these kids have to live," says Trainer, "then there has to be a law that says either the government or some right-to-life group has to provide for their care, and that includes medical, educational and emotional support for the parents, and if the parents still emotionally can't take it, then provide for foster parents. I don't think these children should be sent to an institution."

Parents confronting these awful choices would surely be more inclined to do everything they could to let the baby live if they knew the government would extend a genuinely helpful hand later on. Instead, the Reagan administration is proposing a 30 percent cut in funds for the handicapped, along with numerous changes in regulations that would give states greater flexibility in deciding who is handicapped and how to educate them.

The idea of withholding medical treatment or nourishment from a baby is abhorrent, but if the Reagan administration is going to pressure hospitals into letting these infants live, then it ought not to be cutting out funds and weakening programs that might give them something to live for.