Women and their obstetricians are beginning to accept the advice promulgated for several years by experts: The old notion that all women who have given birth by Caesarean section must always deliver that way is wrong.

A survey of 2,213 physicians by the American College of Obstetricians and Gynecologists found that 63 percent of women who attempted vaginal delivery after a previous Caesarean section succeeded.

"Strides certainly have been made" to convince women and their physicians that vaginal deliveries are safe and successful alternatives to repeat Caesareans, said Mary Jo O'Sullivan, a physician and secretary of the organization.

But she said since about 42 percent of the patients in the survey chose to have another Caesarean, "there is a need to further educate women" about the benefits of vaginal deliveries.

Vaginal delivery is less risky than Caesarean section mainly because the latter is a surgical procedure, said O'Sullivan, associate chairwoman of obstetrics at the University of Miami in Florida.

Also, vaginal births are less expensive, and the woman spends less time in the hospital -- an average of $4,334 and two or three days compared with $7,186 and four or five days for a Caesarean, according to 1989 data from the Health Insurance Association of America.

The rate of Caesarean deliveries rose from 5.5 percent of all U.S. births in 1970 to 24.7 percent in 1988.

But O'Sullivan noted that the increase from 1986 to 1987 and from 1987 to 1988 was 0.3 percent, the smallest rise in five years.

Also, the rate of vaginal births after Caesareans rose from 2.2 percent in 1970 to 12.6 percent in 1988, she said.

O'Sullivan said the rate of repeat Caesareans appears to be tied to the age of the physician. Ninety-eight percent of physicians under 40 said they encourage their Caesarean patients to have vaginal deliveries for subsequent births, compared with 84 percent of physicians over 55.

"It takes a long time to change your practice pattern," O'Sullivan said, noting that some smaller hospitals still do not offer the option of vaginal delivery to women with a previous Caesarean.

As recently as 15 years ago vaginal birth after a Caesarean was not considered good medicine in the United States, though a standard practice for years in many other countries.

The American College of Obstetricians and Gynecologists, the largest professional organization for physicians in those specialties, recommends that women who have had a low transverse incision in a previous delivery and have no medical complications should be encouraged to attempt labor and vaginal delivery in their current pregnancy.

A low transverse incision, which cuts into a non-contracting portion of the uterus, is most commonly used in Caesareans today. It largely replaced what is called the classical incision in which the contracting muscles of the uterus are cut and are more likely to rupture in a subsequent labor.