The main risk factor for ovarian cancer is a positive family history. A history of ovarian cancer on either the mother's or father's side of the family can increase a woman's risk. According to the American Cancer Society, about 5% to 10% of ovarian cancers develop from an inherited tendency.
Mutations in the BRCA1 and BRCA2 genes are associated with a significantly increased lifetime risk of developing ovarian cancer. For those with BRCA1, the risk is estimated to be 35-70% and for BRCA2 it is 10-30%. Women without these mutations have a lifetime risk of about 2%.
The prevalence of ovarian cancer is low in young women (younger than 40) but increases with age, with half the ovarian cancers found in women 63 years of age or older. Most ovarian cancers develop after menopause. Ovarian cancers are more common in Caucasian women than in African American women.
The risk of developing ovarian cancer is increased in women with a personal history of breast cancer and somewhat increased in women who have not had children, are taking fertility drugs, are obese during early adulthood, and perhaps also in those who take hormone replacement therapy or are on fertility drugs. Slightly decreased risks may be associated with women having a tubal ligation (tubes tied), taking oral contraceptives, having children, breast feeding, and being on a low-fat diet.