While progress of a sort continues to be made in high-technology cardiac medicine, the opposite is true in the most natural of hospital procedures: childbirth. The current Journal of the American Medical Association reports the highest rate ever for Caesarean deliveries.

The operation is now performed in one out of five births. A decade ago, it was one out of 10 -- and that was a doubling of the rate in six years. The AMA rightly calls this "unacceptably high." But that hasn't stopped the obstetricians from reaching for the tools of surgery. When women go into labor, the doctors go into gear.

The stethoscopes of obstetricians aren't helping them hear the criticisms within medicine. In 1980, the National Institute of Child Health and Human Development issued a report on C-sections. It said there were too many and called for a decrease.

What's going on? Money and convenience appear to be influencing many obstetricians more than peer opinion. The AMA reports that a Caesarean commands an additional $250 over a vaginal delivery. The hospital also rakes it in. Caesareans require at least three extra days for the mother, and usually much longer for the baby. The additional charges, according to the AMA, total at least $1,550.

The immensity of these profits is better pictured when placed against the annual delivery of 3.5 million newborns. With one-fifth -- or 700,000 -- of those births done by Caesarean costing an extra $250, that comes to $175 million for the doctors and almost $1.1 billion for the hospitals. The new sound of joy heard in delivery rooms is not "It's a boy" or "It's a girl," but "It's a bonanza!"

In addition to more money for the doctors, Caesareans provide more time to spend it. The bother of long labors can be replaced by surgical schedules that get the mothers in and out. Many obstetricians already show up at the last moment for vaginal deliveries, having delegated the waiting chores to residents, interns and nurses who are on duty anyway.

Not all obstetricians, obviously, are guided by money and convenience. Many are physicians of conscience and humility who see childbirth as a natural event, and not a disease or disorder that they, in their almighty wisdom, must cure. They refuse to dictate to women and they want no part of the production-line process that turns labor and delivery rooms into soulless cells dominated by drugs, machines and scalpels.

Many of these physicians, as well as those who advocate Caesareans, belong to the American College of Obstetricians and Gynecologists. The spokesman for this Washington-based professional group claims there are "legitimate reasons" for the increase in Caesareans. He tells of rampant malpractice anxiety, and offers figures.

The average national cost for malpractice insurance for obstetricians is $30,000 a year -- $60,000 and higher in places like New York, California and Florida. About 15 percent of the nation's obstetricians are sued every year and nearly all are sued at least once every five years. Of the suits that go to court, a fourth are settled in favor of the mother. Commonly, hospitals won't give staff positions unless the obstetrician carries $1 million worth of insurance.

Defensive medicine is prescribed. The economics of malpractice pressure the physician into seeing every mother-to-be as a possible litigant-to-be. When the proverbial "complicated pregnancy" or "difficult labor" commences, the obstetrician's impulse is to deliver the baby trouble-free -- and that's by surgery, not nature. Thus, say the obstetricians, don't blame us.

The argument is unpersuasive. Must the doctor's legal concerns come before the rights of the mother and baby? In the labor room, the appearance of fetal distress is no reason to lunge automatically for the Caesarean scalpel. Electronic fetal monitoring for every delivery has yet to be proven either beneficial or necessary. The increasing reliance on Caesareans creates another problem: fewer young doctors coming up will have the skills needed to handle the unexpectedly complex delivery.

One answer to the abuse is to avoid obstetricians whenever possible. More women, especially those who know that most births are safe and routine, are choosing this sound option. The American College of Nurse Midwives, which represents about 85 percent of the professionals in the field, reports 68,000 midwife births in 1982. That is an increase of 80 percent in five years. Home births are also increasing, another bright fact.

Midwives know what they are doing. A recent survey of 1,600 respondents showed that only 5 percent were ever sued for malpractice, against the near-100-percent rate for obstetricians. Legal irks of another kind harass midwives: They have persistent problems in getting laws passed giving them independent hospital privileges.

Obstetricians see nurse midwives -- low-cost, sympathetic and total-care professionals -- as a threat. If they would lay aside their scalpels for a moment, obstetricians might realize the greatest threat is their own heedlessness.