How do I know I am in menopause?

Perimenopause. Menopause is the absence of menses for 12 months. You are probably more interested in peri-menopause. Early peri-menopause is early or late menses by more than 3 days. Late peri-menopause is an absence of menses by more than 3 months but not 12 months. Many women have more symptoms in peri-menopause than menopause.
Check Your FSH Level. If you aren't pregnant, haven't experienced severe trauma or illness recently, haven't had your period in several months, and have an fsh > 25 (blood test), then you are probably in menopause.

Related Questions

How do I know when I am menopausal? My period did not come last month but they have been regular as such. I don't seem to have any symptoms yet?

Go to the doctor. You deserve an examination. I would believe you are menopausal and having bleeding in menopause can represent some significant problems. Please see your gynecologist soon.
Perimenopause. Your ovaries stop producing estrogen and Progesterone over time. Your menstrual periods will stop over time, possibly years. Once your periods stop you are probably in menopause. Some women do not have the symptoms of menopause (i.e. Hot flashes, insomnia, foggy thinking, poor manual dexterity. If these symptoms occur, a health and wellness dr. Like myself can test your hormones using saliva.