In August 2010 Dr Nina Bailey wrote an article on menopause for Bio-Hormone-Health.com
Hot flushes are generally the most characteristic, and often the most distressing, symptom for the menopausal woman. About 75% of women are thought to experience hot flushes, on average around 2 years before their periods actually cease. Of those women who do suffer, around 85% will continue to experience hot flushes for more than 1 year and up to 50% for as long as 5 years.
Those who do suffer are more likely to experience disturbed sleep, depressive symptoms and significant reductions in quality of life as compared to asymptomatic women.
You can read the full article at Bio-Hormone-Health website.