The risk of developing ovarian cancer appears to be affected by several factors; in fact, early age at first pregnancy, older ages of final pregnancy, and the use of low dose hormonal contraception have been associated with a lower incidence of ovarian cancer. There is good evidence that in some women genetic factors are important.

Common risk factors in the development of ovarian cancer include:^[1]

• Common risk factors in the development of ovarian cancer include:
  • Age:
    • There is a proportional association between age and ovarian cancer, as age increases, ovarian cancer incidence increases.^[14]
  • Hormonal and reproductive factors:
    • Early menarche and late menopause:
      • Both increase the frequency of the ovulation and the ovarian epithelium exposure to persistent injury.^[14][15]
    • Nulliparity
      • Studies have shown that multiparity and full term pregnancies decrease the risk of ovarian cancer and fallopian tubal carcinoma.^[16][17]
    • Infertility:
    • Type of infertility and its causes should be taken in consideration as different causes can increase the risk of ovarian cancer such as:^[18]
      • Primary infertility
      • Secondary infertility as endometriosis
      • The role of medications used for ovulation induction in increasing the risks of ovarian cancer is controversial. The association between the fertility drugs and ovarian cancer could be due to the stimulating effect of these drug, however this association is not a causal relation.^[13]
      • Regardless to the fertility medications use, infertility is an independent risk factor of ovarian cancer.^[13]
    • Endometriosis
      • Ovarian cancers that arise from endometriotic tissue usually affect young women and have better prognosis and survival rates.^[19]
    • Polycystic ovarian syndrome:
      • The association is controversial and complex. Meta-analysis found an association between PCOS and endometrial cancer in general but not with ovarian cancer specifically.^[20]
    • Postmenopausal hormone therapy:
      • A non statistical significant association found between combined estrogen–progesteron therapy and ovarian carcinoma.^[21]
      • Meta-analysis found small significant association between ovarian cancer and estrogen therapy alone.^[22]
    • Intrauterine device:
      • Regardless of the type of the IUD, studies have shown an increased risk of ovarian cancer with IUD use.^[23]
  • Genetic factors
    • BRCA gene mutations: the risk of both ovarian and breast cancers increases in women with BRCA mutations.
    • The risk is more with BRCA1 carriers than BRCA2 carriers.^[3]
    • Ovarian cancer develops at an earlier age in BRCA1-carrier women compared to BRCA2-carrier women. Serous adenocarcinoma is the most common type.^[4]
    • General women and women with BRCA mutations usually present with stage III or IV.^[24]
    • However, the grade is higher in women who are BRCA mutations‘ carries.^[25]
    • The short-term survival rate of ovarian cancer in women with BRCA mutations is higher than non-carriers.^[26]
    • Prophylactic bilateral salpingo-oophorectomy can be done in BRCA mutation carries who are at higher risk of developing fallopian tube cancer and primary peritoneal carcinoma.^[27]
  • Lynch syndrome or hereditary nonpolyposis colorectal cancer (HNPCC) :
    • 1 percent of cases with ovarian cancer have Lynch syndrome.^[5]
  • Family history of breast cancer:
    • It is not clear whether the family’s pattern of cancer is due to chance, shared lifestyle factors, a genetic risk passed from parents to children or a combination of these factors.
    • By American cancer society, about 5 to 10% of ovarian cancers are a part of family cancer syndromes resulting from inherited changes (mutations) in certain genes.
    • BRCA mutation carriers with personal or family history of breast cancer have higher risk of developing ovarian cancer that those without BRCA mutation^[28]
  • Other genetic factors:
    • The genes in the Fanconi anemias pathway can undergo different mutations and lead to the development of ovarian and/or breast cancer^[6]. The genes that are associated with ovarian cancer are: BRCA1, BRCA2, BRIP1, RAD51C, RAD51D, PALB2, and BARD1^[7]
  • Environmental factors such as:
    • Cigarette smoking associated with mucinous ovarian cancer^[8]
    • Asbestos,Talc (Its association is controversial)^[9]
  • Other factors such as:
    • Diet:
      • Ddairy food with high animal fat intake is claimed to be associated with ovarian cancer but data are not sufficient to confirm this association.^[10]
    • Exercise:
      • No clear evidence about the association between physical activity and breast cancer.^[11]
    • Obesity:
      • Can increases the risk of ovarian cancer and the risk of its mortality.^[12]
  • Pelvic inflammatory disease can increase the risk of and might be used as tumor marker for ovarian tumor^[29]