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

In early postmenopause, 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 nonhormonal treatments are available for postmenopausal women who have menopausal symptoms. Women are generally encouraged to try nonhormonal treatment to avoid the cancer, heart, and dementia risks of hormone replacement therapy.

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