Professor of Obstetrics and Gynecology at the University of North Carolina Robert C. Cefalo, another expert in the field, said he disagrees with maintaining high rates of caesarean sections, although he said he is skeptical that the percentage could drop to 15 percent.

"Mothers are mortal," he said. "A caesarean delivery is a major surgical operation. There are mothers who die from caesareans."

Cefalo urged hospitals to reduce the number of caesarean sections by better monitoring the labor process and by not rushing to perform the procedure.

In 1994, the American College of Obstetricians and Gynecologists released a statement saying the number of caesarean deliveries in the U.S. is higher than it should be. The College declined, however, to recommend an ideal rate. This October, in a move Sachs said was a step in the right direction, the college published guidelines to aid doctors in determining when to perform vaginal births after a prior caesarean section.

Sachs said managed care companies often provide incentives for hospitals and doctors to perform fewer caesarean sections. Physicians sometimes do not get referrals if their caesarean section rates are too high.

Sachs said he plans to continue his work, performing more studies and compiling more research.

"I think it's an important public health issue," he said. "I think we will see more changes."

The DHHS declined comment yesterday.