Sex hormones are produced by the ovary in the woman, and the testes in the man, to give to each sex its characteristic appearance.
In women, the sex hormone oestrogen that is produced for the first time at puberty causes breast enlargement, hair growth in the armpit and groin, ovulation, the start of menstrual periods and later act to maintain a pregnancy.
If the sex hormones are reduced or lacking, these characteristics get reduced or disappear. This happens naturally during the female menopause. After the menopause, the breasts sag, pubic and armpit hair becomes scanty, and the periods cease due to the lack of sex hormones.
Hormone tablets are the main method of menopause control. While passing through the menopause, it is usual to take one hormone (oestrogen) for three weeks, and a different hormone (progestogen) is added in for the last seven to ten days, and then no hormones are taken for a week. After the menopause has been completed and all periods have stopped, it is usual to take both the oestrogen and progestogen constantly. Other dosage regimes may be recommended.
If oestrogen is taken without progestogen, there is over stimulation of the endometrial tissue in the uterus (womb), which can increase the risk of cancer of the uterus. When the two are taken together, either cyclically (progestogen for only part of the month) or constantly (both hormones all the time) there is no increased risk of uterine cancer. In a hysterectomy the uterus is removed, and so women who have had a hysterectomy cannot have an increased risk of cancer of the uterus, and these women only need to take the oestrogen, and progestogens are unnecessary.
These hormones maintain the body in a near normal balance, while underneath the artificial hormones, the natural menopause is occurring, so that when the tablets are stopped after a year or two, the menopausal symptoms will have gone.
Hormone replacement therapy (HRT) can be given as tablets, skin patches, skin cream, vaginal cream, vaginal pessaries, implants, nasal spray or injection.
Every woman must assess her own needs in consultation with her doctor regarding her lifestyle expectations and the risks of using HRT. Many women are now continuing hormone replacement therapy(HRT) for many years after the menopause to prevent osteoporosis (and the resultant fractured bones), and to slow ageing. Generally speaking, HRT has been a major advance in the health of women, who now outlive men by an average of more than seven years.
Concerns about the safety of hormone replacement therapy (HRT) relate to long-term (greater than five years) use of combined (oestrogen and progestogen) HRT. Short-term use for up to five years is very safe and is used to control the symptoms of menopause (eg. hot flushes, dry vagina, aching).