Neurotoxicity of contraceptive implant.

Since the Food and Drug Administration approved Norplant contraceptive implants in December 1990, almost 1 million women have been injected with the six rods, which parcel out timed- release synthetic progesterone over a 5-year period. But this route to controlling unwanted births-used mostly by poor, inner-city women-may come at a high price, according to preliminary findings by Alan R. Hirsh, a neurologist at Rush-Presbyterian-St. Luke's Medical Center in Chicago.

Hirsh administered a complex battery of psychological, medical, and nerve function tests to five young women who developed recurrent headaches, severe dizziness, depression, and trouble controlling emotions while using Norplant. None had had the implant more than 24 months. In three women, symptoms continued even after their implant was removed.

Last week, at the International Neurotoxicology Conference in Hot Springs, Ark., Hirsh reported that his cognitive tests and electrophysiological assays of discrete nerve and brain functioning confirmed a neurotoxicity that appears to trace to Norplant. He also turned up subclinical disease-changes not yet recognized or described as a problem by the women. These included brain and nerve abnormalities that could underlie numbness in the arms and legs or cognitive problems revealed by the women's memory and problem- solving tests.

Hirsh expressed the greatest concern about the cognitive abnormalities he's diagnosed "because when the brain becomes dysfunctional, it usually doesn't recover." While he plans a large study of randomly selected implant users, he muses "whether we'd have heard of this sooner if a different group was involved"-such as middle-class women, or men.Biomedicine 

Lisa Seachrist reports from Minneapolis at a meeting of the American Society of Human Genetics