Indicators that a woman is nearing menopause include irregular menstrual periods, sleep problems, vaginal dryness, hot flashes and mood swings, explains The North American Menopause Society, or NAMS. This early phase of menopause is called perimenopause. The symptoms of perimenopause occur because ovarian hormones such as estrogen begin fluctuating at uneven levels as a woman nears an end to her fertile years.
Hormonal tests in the forms of saliva testing and follicle-stimulating hormone testing are ineffective at determining whether a woman has entered perimenopause, according to NAMS. One reason for their unreliability is that both estrogen and follicle-stimulating hormone vary throughout a woman's menstrual cycle. The use of birth control pills or other hormone-based therapies can also alter the results of these tests. However, doctors typically do not need hormonal evidence to diagnose perimenopause. A doctor determines whether a woman has begun perimenopause based on her symptoms, medical history and usual menstrual patterns.
Most North American women enter menopause between the ages of 40 and 58, although some begin as early as their 30s or as late as their 60s, notes NAMS. Women commonly begin menopause at around the same age as did their close female members of their immediate families. Once a woman has gone 12 consecutive months without menstruating, the medical community considers her officially to have reached menopause.