What are endogenous estrogens?
Endogenous estrogens are the female sex hormones the body produces as part of the menstrual cycle. Longtime exposure to endogenous estrogens increases the risk of breast cancer. Women who start menstruating before age 12 or begin menopause after age 55 generally have more monthly cycles and therefore a longer lifetime exposure to estrogen. This tends to increase their risk of breast cancer. Women who have never had children or who start their families late also have a higher lifetime exposure to estrogens. Click to Reproductive History.
