ON THIS PAGE: You will find out more about the factors that increase the chance of developing this type of cancer. To see other pages, use the menu on the side of your screen.
A risk factor is anything that increases a person's chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.
The following factors may raise a woman's risk of developing ovarian cancer:
- Age. A woman’s risk of developing ovarian cancer increases with age. Women of all ages have a risk of ovarian cancer, but women over 50 are more likely to develop it. Sixty-eight percent (68%) of women with ovarian cancer are older than 55, and 32% are younger than 55.
- Family history. Women with a first-degree relative (mother, daughter, or sister) with ovarian cancer have about a three times higher risk of developing the disease. This risk increases when two or more first-degree relatives have been diagnosed with ovarian cancer. If you are concerned ovarian cancer may run in your family, it is important to get an accurate family history, including breast cancers in the family. Both breast cancer and ovarian cancers can run together in families so it’s important to tell your doctor about what you discover. By understanding your family history, you and your doctor can take steps to reduce your risk and be proactive about your health (see below).
- Genetics. About 10% to 15% of ovarian cancers occur because a genetic mutation (change) has been passed down within a family. A mutation in the BRCA1 or BRCA2 gene is associated with an increased risk of ovarian cancer; there is also an increased risk of fallopian tube cancer and primary peritoneal (the membrane lining the abdomen) cancer, which are similar to ovarian cancer. While less common, it is possible that BRCA-related ovarian cancer can occur in women who do not have a family history of either breast or ovarian cancer. It is now recommended that all women with ovarian cancer under the age of 70 should consider genetic testing even if they don’t have a family history. Read more about the BRCA1 and BRCA2 genes in the section on hereditary breast and ovarian cancer .
- Obesity. Recent studies have shown that women who were obese in early adulthood are 50% more likely to develop ovarian cancer. Women who are obese are also more likely to die from the disease.
- Endometriosis. This is when the inside lining of a woman’s uterus grows outside of the uterus, affecting other nearby organs. This condition can cause several problems, but effective treatment is available. Researchers are continuing to study whether endometriosis is a risk factor for ovarian cancer but it may increase the risk of certain types of ovarian cancer which include clear cell and endometrioid ovarian cancers.
- Genetic conditions. There are several other genetic conditions linked to an increased risk of ovarian cancer. Some of the most common include:
- Lynch syndrome . Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), increases a woman's risk of ovarian and uterine cancer . It is caused by mutations in several different genes. Lynch syndrome also increases the risk of colorectal cancer , as well as cancer of the stomach , small intestine , liver , bile duct , urinary tract , brain and central nervous system , and possibly breast .
- Peutz-Jeghers syndrome (PJS) . PJS is caused by a specific genetic mutation and is associated with multiple polyps in the digestive tract that become noncancerous tumors and increased pigmentation (dark spots on the skin) on the face and hands. In addition to an increased risk of ovarian cancer, PJS also raises risk of breast , uterine , and lung  cancer, but is very uncommon.
- Nevoid basal cell carcinoma syndrome (NBCCS) . Women with NBCCS, also called Gorlin syndrome, have an increased risk of developing fibromas, which are benign fibrous tumors of the ovaries. There is a small risk that these fibromas could develop into a type of ovarian cancer called fibrosarcoma. People with NBCCS often have multiple basal cell carcinomas  and jaw cysts and may develop medulloblastoma  (a type of brain tumor) in childhood.
- Women with Li-Fraumeni syndrome  and ataxia-telangiectasia  may also have a slightly increased risk of developing ovarian cancer.
Only genetic testing  can determine whether a woman has a genetic mutation. Most experts strongly recommend that women considering genetic testing first talk with a genetic counselor , which is an expert trained to explain the risks and benefits of genetic testing.
- Breast cancer. Having a diagnosis of breast cancer increases the risk for ovarian cancer, even when the BRCA genetic mutation test is negative (see above).
- Ethnicity. Women of North American, Northern European, or Ashkenazi Jewish heritage have an increased risk of ovarian cancer.
- Reproductive history. Women who have never had children, have unexplained infertility (the inability to bear children), have not taken birth control pills, or had their first child after the age of 30 have an increased risk of ovarian cancer. Also, women who started menstruation before age 12 and/or go through menopause later in life have an increased risk of ovarian cancer.
- Hormones. Women who have taken estrogen-only hormone replacement therapy (HRT) after menopause may have a higher risk of ovarian cancer.
Different factors cause different types of cancer. Researchers continue to look into what factors cause this type of cancer. Although there is no proven way to completely prevent this disease, you may be able to lower your risk. Talk with your doctor for more information about your personal risk of cancer.
Research has shown that certain factors may reduce a woman's risk of developing ovarian cancer:
- Taking birth control pills. Women who took oral contraceptives for three or more years are 30% to 50% less likely to develop ovarian cancer.
Women who have had a hysterectomy or a tubal ligation may have a lower risk of developing ovarian cancer. A hysterectomy is the removal of the uterus and, sometimes, the cervix. Tubal ligation is having the fallopian tubes tied surgically to prevent pregnancy. A salpingectomy, which is the removal of the fallopian tubes, is also sometimes recommended for women with a risk of ovarian cancer.
For women with mutations in the BRCA1 or BRCA2 mutation, which cause 5% to 10% of all breast cancer and 15% of all ovarian cancer. Having the ovaries and fallopian tubes removed after childbearing is sometimes done to prevent breast and ovarian cancer. This can help with risk reduction ranging from a 70% to 96% reduction in ovarian cancer, and a 40% to 70% reduction in breast cancer. It is very important for women considering this surgery to talk with their doctor and a genetic counselor  to fully understand the risks and side effects of this surgery compared with the risk of developing ovarian cancer.
The next section in this guide is Symptoms and Signs  and it explains what body changes or medical problems this disease can cause. Or, use the menu on the side of your screen to choose another section to continue reading this guide.