Breast augmentation (enlargement) surgery is usually done on an outpatient basis but under general anesthesia. It is often performed when one breast is noticeably smaller than the other or if both breasts are smaller than usual for a woman's particular body type. A small incision is made in one of a number possible locations (selected to minimize visible scars) and an implant is inserted. The implants exterior is made of a pliable silicone material and filled with either saline (salt water) or silicone. The implant can be placed either under or on top of the chest muscle depending on the desired final appearance and body type. Many women prefer the silicone type because it appears and moves more like natural breast tissue. For a number of years silicone implants were not available in the U.S. but after exhaustive review and research they have been again certified as safe. The procedure takes about two hours and there will be a period of a few days that there will be a fair amount of moderate pain requiring pain medications. Your doctor will give you specific post surgery instructions which will certainly involve restricting strenuous activity for a couple of weeks (possible longer if the implant is placed under the chest muscle.