What Is the Main Cause of Ovarian Cancer?

Reviewed on 5/17/2021
Ovarian cancer
One theory suggests that cancer-causing agents may enter through the vagina and pass through the uterus and fallopian tubes to reach the ovaries.

There is no exact cause as to what leads to ovarian cancer. However, scientists have come up with several theories linked with ovarian cancer.

Ovulation (number of times the ovary releases an egg)

Some researchers suggest that there is a relationship between ovulation and the risk of developing ovarian cancer. For example, pregnancy and birth control pills can reduce the risk of ovarian cancer. As both pregnancy and birth control pills lower ovulation, it reduces the risk of ovarian cancer. Women who have an early onset of periods (menarche) and late menopause have more ovulation episodes, so they are at a higher risk of ovarian cancer.

Entry of cancer-causing substances through the vagina

One theory suggests that cancer-causing agents may enter through the vagina and pass through the uterus and fallopian tubes to reach the ovaries. Uterus removal (hysterectomy) or blocking of the fallopian tube (tubal ligation) can alleviate the risk of ovarian cancer by blocking cancer-causing substances.


Another theory states that male hormones (androgens) can increase the risk of ovarian cancer.

Other causes of ovarian cancer are

  • Gene changes related to ovarian cancer:

Scientists have made progress in understanding the role of deoxyribonucleic acid (DNA) in causing normal cells to become cancer. DNA is the source of instructions for everything that cells do.

DNA consists of genes that are responsible for providing instructions to control cells’ growth and division. Two types of genes are associated with cancer development:

  1. Oncogenes: These genes promote cell division.
  2. Tumor suppressor genes: These genes slow down cell division or make cells die at the right time. They ensure that cells with a DNA defect are repaired or killed before they make more defective cells of their kind.

DNA mutations causing the activation of oncogenes and inactivation of tumor suppressor genes can lead to cancer. There are two ways to get mutated DNA:

  1. Inherited genetic mutations: Some people may inherit the mutated DNA from their parents. The genes responsible for increasing the risk of ovarian cancer are called breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2). However, most ovarian cancers are not caused by inherited DNA mutations. Women with a family history of breast, ovarian, thyroid, uterine and/or colorectal cancer should consult their physician about genetic counseling and testing.
  2. Acquired genetic changes: Most mutations in ovarian cancer are not inherited but may occur during a woman’s lifetime. These are known as acquired mutations. In some cancers, acquired mutations have been linked to exposure to radiation or cancer-causing chemicals. However, studies have not specifically linked any single chemical in the environment or diets to mutations that cause ovarian cancer. The cause of most acquired mutations remains unknown.

What Are the Risk Factors of Ovarian Cancer?

There is no sure way to know if a woman will get ovarian cancer. Most women who get ovarian cancer don’t come under the high-risk category. However, several factors may escalate a woman’s risk of ovarian cancer, which include

  • Having an Eastern-European Jewish (Ashkenazi) background
  • Have never been pregnant
  • History of endometriosis
  • History of breast, uterine, or colorectal cancer
  • Undergoing estrogen hormone replacement therapy
  • Early menarche and late menopause
  • Aged 50 years or older

How to Prevent Ovarian Cancer

Some of the following measures may help prevent ovarian cancer:

  • Using birth control pills for five years or more
  • Getting a tubal ligation, hysterectomy
  • Giving birth to a child
  • Breastfeeding for a year or more may modestly reduce the risk of ovarian cancer

These preventive measures are not recommended for everybody. Moreover, following these measures may lower the chances, but it doesn’t mean this won’t lead to cancer.


Where does ovarian cancer occur? See Answer

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Reviewed on 5/17/2021
American Cancer Society. What Causes Ovarian Cancer? https://www.cancer.org/cancer/ovarian-cancer/causes-risks-prevention/what-causes.html

Cleveland Clinic. Ovarian Cancer. https://my.clevelandclinic.org/health/diseases/4447-ovarian-cancer

Centers for Disease Control and Prevention. What Can I Do to Reduce My Risk of Ovarian Cancer? https://www.cdc.gov/cancer/ovarian/basic_info/prevention.htm