There is a stage of life leading up to Menopause called Perimenopause and a stage of life when Menopause is finished called Post-menopause.

Menopause itself is also a stage and seldom occurs overnight. For lots of women it happens in their 50's to 60's. Recent studies and research are reporting that today's women are beginning menopause earlier possibly due to taking having taken birth control pills (synthetic hormones), eating synthetic hormone-laden meats and eggs, and living very stressful lifestyles, or it can be brought on earlier by surgical intervention.

All women transition through these three phases, and with menopause occurring earlier for many women, the first phase is logically pushed earlier as well.

More information – Perimenopause