This large, 10-year observational study is being conducted to compare the long-term safety and performance of NATRELLE® silicone gel-filled breast implants with saline implants or national norms. Participants in the study are contributing to the health and safety of all women with breast implants. The FDA required Allergan® to perform the BIFS study in response to safety concerns about silicone breast implants, and updates regarding study status are reported annually to the FDA.