Premenopause is the time before perimenopause starts, when there are no noticeable menopausal
symptoms – yet. Whereas perimenopause is the transitional phase leading up to menopause, where
hormonal changes begin to occur and symptoms like irregular periods, hot flashes, and mood swings
may be present. When in the perimenopause phase, the levels of circulating estrogen begin to change.
Quantity and quality of follicles begin diminishing, which causes fewer ovulations and lower
progesterone levels to account for changes in estrogen.
The symptoms become even more pronounced during the menopause phase. After menopause, women
do not ovulate or menstruate and blood estrogen levels drop dramatically. Menopause marks the end of
your menstrual cycle and is diagnosed after you have gone 12 months without a menstrual period. The
average age a woman reaches menopause is about 51; however, the natural biological process can
happen in your 40s or 50s. Surgical menopause can occur at any age if the ovaries are removed.
