Typically, this will involve a rapid decline in ovarian function and significantly reduced production of sex hormones (principally oestrogens). The resulting amenorrhoea (permanent cessation of menstruation) signals the end of a woman' s ability to have children.

What happens to hormone levels during the menopause?

The menopause has a profound effect on production of the two female sex hormones, oestrogen and progesterone, which are central to regulating the menstrual cycle.

During the perimenopausal period, levels of oestrogen and progesterone fluctuate, and a woman will experience irregular menstruation. There may also be unpredictable episodes of heavy bleeding until, eventually, periods stop altogether.

Women who have to undergo surgery to remove the uterus (hysterectomy) will experience an abrupt end to their menstrual cycle. However, only if both ovaries are removed at the time of surgery, will a woman go through the menopause immediately after this surgery.

What symptoms are associated with the menopause?

The first signs of menopause (the beginning of the peri-menopausal period) will usually start with irregular periods.

This phase can last from a few months to a few years.

The complete absence of menstruation over a one-year period is regarded by doctors as a firm sign that a woman is post-menopausal.

The associated hormonal changes can have a profound effect on the neuroendocrine system and can induce hot flushes, night sweats, palpitations, insomnia, loss of energy and libido (sex drive), mood changes, anxiety, and irritability.

In many women these symptoms have significant effects on daily life and on their overall quality of life.

The loss of oestrogen can also lead to adverse effects on the urogenital tract, which may include drying and thinning (atrophy) of the vagina, incontinence, pruritis (vaginal itch) and dyspareunia (pain and discomfort during sexual intercourse).

The dermatological changes which are most likely to occur include a marked thinning of the skin, a reduction in the number of sweat glands, and a loss of pubic hair and hair under the arms. Hair and skin in general become more fragile as the menopausal phase sets in.

One of the more important consequences of menopause includes progressive loss of bone mass often leading to osteoporosis. Osteoporosis can result in fractures of the wrist, hip and spine, although any bone could be affected.

This consequence carries a heavy burden for the individual concerned and for society, due to the resulting cost of therapy and often long periods of rehabilitation. Prevention is therefore important.

What health risks are associated with the menopause?

Menopausal symptoms, such as hot flushes, urogenital atrophy, reduced energy and drive, can significantly impair a woman' s health and sense of well-being.

Postmenopausal women frequently experience diminished quality of life and/or self-esteem. These physiological symptoms can result in a variety of psychosocial symptoms, such as sexual dysfunction, decreased libido, sleep deprivation, mood disorders, anxiety and depression.

Osteoporosis is one of the long-term effects of the menopause. Oestrogen deficiency is associated with an increased intensity in bone resorption but decreased bone formation. This leads to overall bone loss, reduced bone quality and reduced load-bearing strength (osteoporosis), resulting in an increased risk of bone fractures.

A number of large clinical studies have shown that oestrogen is effective in preventing and even partially reversing postmenopausal bone loss, and this in turn reduces the incidence of vertebral and hip fractures.

The incidence of cardiovascular disease increases significantly in women at the time of the menopause, and oestrogen depletion is likely to play a role in this increased risk.

Recent studies released by the Malaysian Health Ministry show that 46% of women around the age of 50 suffer from heart disease.

The mechanisms behind this are complex, and involve other factors associated with oestrogen depletion, such as increased susceptibility to raised blood pressure, weight gain and high cholesterol levels.

High blood pressure (hypertension) is particularly dangerous because it contributes to coronary heart disease and stroke.