The risk for developing ovarian cancer appears to be affected by several factors.

The more children a woman has, the lower her risk of ovarian cancer. Early age at first pregnancy, older ages of final pregnancy and the use of low dose hormonal contraception have also been shown to have a protective effect. Ovarian cancer is reduced in women after tubal ligation.

The link to the use of fertility medication, such as Clomiphene citrate, has been controversial.

An analysis in 1991 raised the possibility that use of drugs may increase the risk for ovarian cancer. Several cohort studies and case-control studies have been conducted since then without providing conclusive evidence for such a link. [2] It will remain a complex topic to study as the infertile population differs in parity from the "normal" population.

There is good evidence that in some women genetic factors are important. Carriers of certain mutations of the BRCA1 or the BRCA2 gene, more frequent in some populations (e.g. Ashkenazi Jewish women) are at a higher risk of both breast cancer and ovarian cancer, often at an earlier age than the general population.

Patients with a personal history of breast cancer or a family history of breast and/or ovarian cancer, especially if at a young age, may have an elevated risk.

A strong family history of uterine cancer, colon cancer, or other gastrointestinal cancers may indicate the presence of a syndrome known as hereditary nonpolyposis colorectal cancer (HNPCC, also known as Lynch II syndrome), which confers a higher risk for developing ovarian cancer. Patients with strong genetic risk for ovarian cancer may consider the use of prophylactic oophorectomy after completion of child-bearing.