Perimenopause

Perimenopause is defined as the transitional period from normal menstrual periods to no periods at all. The transition can, and usually does, take up to ten years. During the perimenopausal transition you may experience a combination of PMS and menopausal symptoms or no symptoms at all.

During perimenopause, the production of most of the reproductive hormones, including the estrogens, progesterone and testosterone, diminish and become more irregular, often with wide and unpredictable fluctuations in levels. During this period, fertility diminishes, but is not considered to reach zero until the official date of menopause. The official date is determined retroactively, 12 months after the last appearance of menstrual blood. Signs and effects of the menopause transition can begin as early as age 35, although most women become aware of the transition in their mid to late 40s, often many years after the actual beginning of the perimenopausal window.

In the perimenopause years, many women undergo noticeable and clinically observable physical changes resulting from hormonal fluctuations. The most well-known effect of these is the "hot flash" or "hot flush", a sudden temporary increase in body temperature. The "flash" sensation in a "hot flash" occurs as the body temperature soars upward at a rapid rate and reaches a peak mere fractions of a second after the onset of the temperature increase is first noticed. The "hot" sensation in a "hot flash" is not the initial temperature rise; instead, it is a reaction to the perceived slowness of the body's return to a more normal temperature range when compared to the speed of the run-up to the spike.