O'Connor said that though all implant patients are probably upset by the news about the dangers of silicone implants, the 20 percent who had reconstruction following surgery for medical reasons--rather than for cosmetic reasons--are most likely the hardest hit.

"The question now is: how much should women worry?" O'Connor said. "No one knows."

Doctors who are still doing implant operations are now using saline implants, which consist of a silicone envelope containing saline solution.

Implants filled with saline are less popular than those filled with silicone gel because they have a less satisfactory shape and consistency, a "splash and ripple effect" and a tendency to break after implantation.

"One to two percent of [saline implants] leak every year," said O'Connor. "You could wake up one morning and your breast would be flat on that side."

Dr. David S. Rosenthal, director of University Health Services (UHS), said he did not know of any Harvard students' having problems with breast implants, and that the number of students who have had implants is probably very low.

However, Rosenthal added, several people who are not affiliates of the University but do receive health care at UHS have been less fortunate.

"We've had a few people with problems at UHS," said Rosenthal. "We've sent out a warning to the providers who are taking care of those persons."

Rosenthal said that breast implant patients are generally scheduled for a yearly check-up.