I am 35 and would like to know at what age one starts going through menopause. What are the symptoms? I may be starting now so I would like to know.

--Libby

The average age of menopause in American women is 51, with a range of 48-55. By definition, menopause is the lack of a menstrual period for one year. Menopause is not like turning off a light switch -- one minute you're menstruating and the next you're in menopause. It's more like a dimmer switch: For several years before actual menopause, subtle changes in hormone levels occur, and symptoms may begin. These symptoms may include irregular periods, hot flashes, night sweats, vaginal dryness and mood swings. You may want to read my previous column on Approaching Menopause for additional information and some reading material.

In your case, if you are truly undergoing the hormonal changes associated with menopause at age 35, we would call it premature ovarian failure. This is diagnosed by blood tests indicating a menopausal level of FSH (follicle - stimulating hormone) on several occasions. Premature ovarian failure may be associated with autoimmune disorders, such as some types of thyroid disease, myasthenia gravis and rheumatoid arthritis. If premature ovarian failure is diagnosed, you should have a battery of other tests performed as well. Often this evaluation is conducted by an endocrinologist (either reproductive or medical).