Hysteroscopic sterilization is an incisionless gynecologic procedure in which the fallopian tubes are essentially “plugged” to prevent a woman from becoming pregnant. In the Essure sterilization method, which has been in use since 2002, two small metal springs called micro-inserts are positioned in each fallopian tube. These implants eventually cause scar tissue to form in the space around them, thereby creating a natural obstruction of the tubes. This 30-minute procedure can be performed on an outpatient basis and without general anesthesia. Women need to realize that the procedure is not immediately effective, and that they can become pregnant before the needed scar tissue develops. Approximately three months are required between the time that the implants are inserted and the fallopian tubes are fully blocked. After this amount of time, your doctor will order an imaging study called hysterosalpingography (HSG) to ensure that the blockage is complete.