Tubal ligation is used as a form of birth control. It involves the physical disruption of the fallopian tubes. The fallopian tubes are the pathway for the egg from the ovary to the uterus. If the egg is fertilized, it can implant in the uterus and cause pregnancy.
Tubal ligations prevent pregnancy by preventing contact between the egg and sperm.
The egg is simply reabsorbed by the body. There are many methods for tubal ligations. They are classified by how they are done. The most common method is called the Pomeroy. The Pomeroy involves the creation of a loop in the fallopian tube, which is tied off.