It took Kay Perrin only a week to realize something was wrong.

It was fall 1987, and Perrin, a nurse at Tampa General Hospital, in Tampa, Fla., had just been transferred temporarily to the outpatient, high-risk obstetrical unit. She noticed something unusual. Pregnant, mostly indigent women, some of whom spoke or understood only Spanish, were coming in for their second and third amniocentesis. Some had had even more.