Which of the following reduces the risk of epithelial ovarian cancer?

Oral contraceptive use reduces the risk of epithelial ovarian cancer. Women who use oral contraceptives for 5 or more years reduce their relative risk to 0.5 (i.e., there is a 50% reduction in the likelihood of development of ovarian cancer).The oral contraceptive pill is the only documented method of chemoprevention for ovarian cancer, and it should be recommended to women for this purpose. When counseling patients regarding bih control options, this impoant benefit of oral contraceptive use should be emphasized. This is impoant for women with a strong family history of ovarian cancer.