 Less commonly, tubal ligation procedures may also be performed for patients who are known to be carriers of genes that increase the risk of ovarian and fallopian tube cancer, such as BRCA1 and BRCA2.While the procedure for these patients still results in sterilization, the procedure is chosen preferentially among these patients who have completed childbearing, with or without a simultaneous oophorectomy.Most methods of female sterilization are approximately 99% effective or greater in preventing pregnancy.