III.

Risk Factors for Ovarian Cancer

Although a woman’s likelihood of developing ovarian cancer is small, certain factors increase her chances of developing the disease. Women with a close female relative (a mother, sister, or daughter) who has ovarian cancer have an increased risk of developing the disease. Having two close relatives with the disease increases the risk even more. A woman who has a mutated version of a gene called BRCA1 or a gene called BRCA2 has a significantly increased risk for developing ovarian cancer or breast cancer. A woman who has had cancer of the breast, uterus, or colon also has a higher risk for ovarian cancer. The risk for ovarian cancer increases with age: Most cases occur in women over age 55.

Giving birth appears to reduce a woman’s chances of developing ovarian cancer, possibly because pregnancy reduces the number of times a woman ovulates (releases an egg). Women who have never been pregnant have a higher risk than women who have had a child. Having several pregnancies seems to further lower a woman’s risk for the disease.