Which of the following are recognized risk factors for ovarian cancer?

Nulliparity, or not having given birth, is indeed recognized as a risk factor for ovarian cancer. Women who have never been pregnant have a higher risk compared to those who have had children. This is partially due to the fact that each ovulation carries a risk of potential mutations and malignancy. The more times a woman ovulates, the greater her exposure to hormonal fluctuations that may increase cancer risk. Therefore, not having experienced pregnancy, which generally reduces the number of ovulatory cycles a woman has, can contribute to a higher likelihood of developing ovarian cancer.

In contrast, factors like a history of breastfeeding and previous use of oral contraceptives are generally associated with a reduced risk of ovarian cancer. Breastfeeding can lead to fewer ovulatory cycles, and oral contraceptives have protective effects due to hormonal regulation, reducing overall ovulation. A history of breast cancer can indicate certain genetic profiles or predispositions, but it is not universally classified as a direct risk factor for ovarian cancer, even though there may be overlapping genetic concerns, particularly in mutations such as BRCA1 and BRCA2, which increase the risk for both cancers.