Q: What are the risk factors for ovarian cancer?

We know that the following can affect the risk, but none of these factors influence risk as much as a strong family history of the disease:

• Using the combined oral contraceptive pill halves your risk if you have used it for 5 years or more.
• Using other types of hormonal contraception (minipill, injectable contraception, contraceptive implants) can reduce your risk of ovarian cancer.
• Breastfeeding reduces the risk of ovarian cancer.
• The more children you have had, the lower your risk of ovarian cancer.
• Having a sterilisation operation (clips placed on the Fallopian tubes) reduces the risk of ovarian cancer.
• Taking hormone replacement therapy (HRT), having endometriosis, being overweight or smoking all slightly increase the risk of ovarian cancer.
• Using talc on the genital area may cause a small increase in risk.
• Exposure to asbestos may cause a small increase in risk.
• Some fertility treatments may cause a slight increase in risk, but this risk is small and probably confined to women who do not achieve a successful pregnancy following fertility treatment. Also, fertility treatment probably only increases the risk of borderline ovarian tumours which tend to have a very good prognosis.
• Recent evidence has suggested that premenopausal women with polycystic ovarian syndrome (which is different to just having polycystic ovaries) may have a slightly higher risk of ovarian cancer. -- see Does anything apart from my family history affect my risk of ovarian cancer