The post-menopausal phase of a woman's life begins at menopause, which is 1 year after her last menstrual period. While post-menopause usually begins around age 50, some women become post-menopausal in their mid-40s, and others do so in their later 50s.

In early post-menopause, a woman's estrogen stabilizes at a low level. Although low estrogen helps reduce the risk of various types of cancer, it also leads to bone thinning, which sometimes results in osteoporosis. A variety of hormonal and non-hormonal treatments are available for post-menopausal women who have menopausal symptoms. Women are generally encouraged to try non-hormonal treatment to avoid the cancer, heart, and dementia risks of hormone replacement therapy.

Menopause can begin early and suddenly after removal of the ovaries or after cancer treatment that damages the ovaries.