Last updated: 04 October 2011
The menopause is sometimes known as the 'change of life' and is marked by the ending of menstruation (when a woman's periods stop).
A woman’s periods do not usually stop suddenly. They generally become less frequent, the odd period is missed and then they stop altogether.
When it happens
In the UK, the average age for a woman to reach the menopause is 52.
A woman is said to have reached the menopause once she has not had a period for one year. After this point, she can be described as post-menopausal.
If the menopause occurs in a woman who is under 45 years of age, it is known as premature menopause. It is estimated that premature menopause affects 1% of women under the age of 40 and 0.1% of women under the age of 30.
During the time leading up to the menopause (perimenopause), the hormonal and biological changes that are associated with the menopause begin. As a result of these hormonal changes, many women experience both physical and emotional symptoms, such as hot flushes, night sweats and irritability (see Symptoms of menopause for more information).
The menopause is the end of egg production (ovulation). This occurs as a result of falling levels of the female sex hormone oestrogen, which regulates a woman’s periods.
Most women reach the menopause without seeking medical advice. However, treatments are available that can ease menopausal symptoms that are severe or distressing (see Treatment for menopause for more information).
Continue to next section: Symptoms of the menopause