Chapter 12 Menopause and premature ovarian failure
Definitions. Natural menopause is the permanent ceasing of menstruation resulting from the loss of ovarian follicular activity. Menopause is by definition only after 12 months of amenorrhoea with no other pathological cause. Menopause is the final period diagnosed only in retrospect. Perimenopause is the time immediately premenopause, as characterised by endocrinological and clinical features, and continuing until the year postmenopause. Premature menopause occurs at an age <2 standard deviations from the community mean. In practice, this is menopause prior to the age of 40. The average age of menopause is 50–51 years.
