Hormone replacement therapy (HRT) is a treatment used to replace the female hormones that a woman’s body is no longer producing because of the menopause.
The menopause – sometimes known as the ‘change of life’ – occurs when levels of the female hormones oestrogen and progesterone fall and your ovaries stop producing eggs. Menstruation (your periods) ends and you are no longer able to conceive (become pregnant).
Oestrogen and progesterone have very important roles in a woman’s body; when levels fall, this causes a wide range of both physical and emotional symptoms. HRT can restore these hormone levels and help the body function normally again.
The role of oestrogen
Oestrogen plays an important role in the release of eggs from the ovaries. It regulates a woman’s periods and helps her to conceive.
Oestrogen also helps regulate many other body functions, including bone density, the temperature of your skin and keeping the vagina moist. It is the reduction of oestrogen that causes most of the symptoms associated with the menopause, including:
- hot flushes
- vaginal dryness
- loss of sex drive
- mood changes
- stress incontinence (leaking urine when you cough or sneeze)
- night sweats
- thinning of the bone, which can lead to brittle bones (osteoporosis)
Most of these symptoms pass within two to five years, although vaginal dryness is likely to get worse if it is not treated. The risk of osteoporosis also increases with age.
The role of progesterone
The main function of progesterone is to get the womb ready for a possible pregnancy. It also helps protect the lining of the womb (endometrium).
A falling level of progesterone does not have the same wide-ranging effects on your body as falling levels of oestrogen. However, it does increase your risk of developing cancer of the womb lining (endometrial cancer).
For this reason, progesterone is usually used in combination with oestrogen in HRT (although women who have had a hysterectomy do not need progesterone and can take oestrogen-only HRT). See HRT - types for more information.
Benefits and risks
HRT has been extensively studied and a great deal of information is known about both the benefits and risks.
The main and most obvious benefit of HRT is that it has proved very successful in controlling the symptoms of the menopause. Taking HRT can make a huge difference to a woman’s quality of life and wellbeing.
HRT can also reduce a woman’s risk of developing osteoporosis and cancer of the colon and rectum. However, the long-term use of HRT to prevent osteoporosis is not usually recommended. This is because HRT slightly increases the risk of developing breast cancer, endometrial cancer, ovarian cancer and stroke, and there are other medicines available for osteoporosis that do not carry the same level of associated risk. For more information, see HRT - risks
Most experts agree that if HRT is used on a short-term basis (no more than five years) then the benefits of it outweigh any associated risk. If it is taken for longer, especially for more than 10 years, you should discuss your individual risks with your GP and review these risks on a yearly basis.