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Risks and Causes

Risks and Causes

We don’t know the exact causes of most ovarian cancers. However, we do know there are factors that may increase a person's risk of developing ovarian cancer.

Some of the known risk factors for ovarian cancer include:

Increasing Age

Getting older is the biggest risk factor for developing ovarian cancer. Ovarian cancer can happen at any age, but it is usually in women who have been through menopause, with the average age of diagnosis being age 64.

Hereditary Factors

These account for approximately 20% of ovarian cancers. Hereditary factors include:

  • inheriting a faulty gene such as a mutation in BRCA1 or

  • BRCA2 genes. Women of Ashkenazi Jewish descent have

  • a higher incidence of BRCA mutations than the general population

  • having a strong family history of ovarian, breast or some other cancers (colorectal or endometrial).

Other Ovarian Cancer Risk Factors

Other factors that may increase the risk of ovarian cancer include:

  • having endometriosis, a previous breast cancer or diabetes

  • use of hormone replacement therapy (HRT) (this applies to some ovarian cancer types)

  • being overweight

  • smoking, which may slightly increase the risk of developing

  • mucinous ovarian cancer

  • not having had children – women who have not had children are at a slightly higher risk.

Reducing your risk of ovarian cancer:

What are risk factors for ovarian cancer?

A risk factor is any factor that is associated with increasing someone’s chances of developing a certain condition, such as cancer. Some risk factors are modifiable, such as lifestyle or environmental risk factors, and others cannot be modified, such as inherited factors and whether someone in the family has had cancer.

Having 1 or more risk factors does not mean that you will develop cancer. Many people have at least 1 risk factor but will never develop cancer, while others with cancer may have had no known risk factors. Even if a person with cancer has a risk factor, it is usually hard to know how much that risk factor contributed to the development of their disease.

Factors that are associated with a higher risk of developing ovarian cancer include:

  • a family history of ovarian cancer – the risk of developing ovarian cancer is higher if 1 or more blood relatives (such as mother, sister or daughter) has had ovarian cancer

  • family history of breast or colon cancer

  • a mutation in 1 of several known genes. Up to 15% of all cases of invasive ovarian cancer involve the inheritance of a mutated gene. Women who have inherited mutations in the BRCA1 or BRCA2 genes have a substantially increased risk of ovarian and breast cancer. Women with Lynch syndrome (also known as hereditary nonpolyposis colon cancer or HNPCC) also have an increased lifetime risk of ovarian cancer

  • increasing age

  • medical conditions such as endometriosis

  • use of hormone replacement therapy (HRT)

  • tobacco smoking

  • obesity

Some factors reduce the risk of developing ovarian cancer. These include:

  • having children

  • use of the oral contraceptive pill (the pill)

  • gynaecological surgery – tubal ligation (having your tubes tied)

It is not clear whether the following affect the risk of ovarian cancer:

  • Diet

  • Alcohol

  • Aspirin and non-steroidal anti-inflammatory drugs

  • Talc

This information was taken from the Cancer Australia website.

More information:

Ovarian Cancer Australia have developed a factsheet for people with a family history of ovarian cancer, with information on where to seek further guidance and support.


Genetics Factsheet

This fact sheet is for individuals with a family history of ovarian cancer, providing information on how this may impact their risk of developing cancer and where they can seek further information and guidance.

  • To speak with an Ovarian Cancer Nurse for more information and support please phone the Ovarian Cancer Australia Helpline on 1300 660 334 Monday-Friday during business hours, or email support@ovariancancer.net.au

Want to talk?

Ovarian Cancer Australia's Helpline is available to call 9am - 5pm AET Monday to Friday 

Related Pages

Understanding Ovarian Cancer

Ovarian cancer is an umbrella term for many different types of the disease. Through ongoing research, we are learning so much more about what it is, how it behaves, and how best to treat it. 

Genetics and Ovarian Cancer

Many people wonder what caused their cancer. They also worry it may be a hereditary cancer that other family members may get. You may also be a family member of someone diagnosed with ovarian cancer, concerned about your own risk of developing a cancer yourself.

Ovarian Cancer Symptoms & Signs

Learn the signs and symptoms of ovarian cancer. There is no early detection test for ovarian cancer, so all women need to be aware of the signs and symptoms of ovarian cancer.

Acknowledgement flags

Ovarian Cancer Australia acknowledges the Traditional Owners of the land where our office is located, the Wurundjeri people of the Kulin Nation and we pay our respects to Elders past and present.