You are seeing a 62-year-old woman with a family history of breast cancer. She is worried about her future risk of breast cancer, since her mother died of breast cancer at the age of 63. Which of the following features is also a recognized risk factor for breast cancer?

Breast cancer risk is reduced by 20% for each year that menarche is delayed. Early menopause, natural or surgical, also decreases risk. Early (age 18 or 19) full-term pregnancy and multiparity decrease the risk. Radiation exposure is a risk factor primarily in adolescence and is marginal after the age of 40. In summary, there are three important dates in the assessing the risk of breast cancer: age of menarche, age of first full-term pregnancy, and age of menopause.