The Essure device is a form of permanent contraception for women. It’s comprised of small, flexible coils made of nickel-titanium alloy (nitinol) and polyester fibers. The coils are inserted into the fallopian tubes through the cervix and uterus. Once inserted, the Essure coils trigger the growth of scar tissue, which blocks the fallopian tubes and prevents sperm from fertilizing the eggs. Over time, this causes permanent sterilization, effectively preventing pregnancy.