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.

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