What is HRT?

Hormone replacement therapy (or HRT) is the replacement of female sex hormones oestrogen and progesterone in women to control symptoms of the menopause.

What is hormone replacement therapy?

Just as the name implies hormone replacement therapy (HRT) is a replacement of female sex hormones in women. These hormones are called oestrogen and progesterone. They are released from the ovaries and influence changes in the body’s cycle which controls periods, moods and may contribute to a sense of wellbeing and healthiness. Oestrogen is also very important to maintain strong, healthy bones. Usually every month in a healthy woman of childbearing age hormones are produced and released from the brain and pituitary gland to encourage one of her two ovaries to produce an egg (ovum). At the same time oestrogen and progesterone are released from the ovaries, which cause changes that help to prepare the body for a pregnancy.

If pregnancy does not occur the hormone levels fall and the woman will have a period. After the menopause or ‘the change’ the ovaries no longer respond to the hormones from the pituitary gland and shut down. This means a woman can no longer become pregnant naturally and her periods stop. At this time symptoms may appear, including hot flushes, night sweats, insomnia, palpitations, mood changes, vaginal dryness and painful intercourse, and mild skin changes such as dryness and loss of elasticity. Treating patients with HRT replaces the hormones no longer being released from the ovary and some of these symptoms can be helped. 

When can hormone replacement therapy be used?

Most women have their menopause between 50-55 years of age. Some women go into an early menopause before they are 45. In these women HRT can be used before the age of 50 without increasing their risk of breast cancer. Most women are postmenopausal by 54. The symptoms of the menopause may last any time from one to five years, and some women still experience hot flushes some 10 years after their menopause began. Some may not have hot flushes at all.   

What types of therapy are there?

HRT can be given by tablets, patches, creams or gels under advice from a GP. HRT can take different forms:

  • Oestrogen only; for women who do not have a uterus (womb)
  • Cyclical combined – which is oestrogen and progesterone together and re-introduces monthly periods
  • Continuous combined – these prevent periods and may either be oestrogen and progesterone combined or Tibolone – a synthetic medication that has combined effects of oestrogen, progesterone and testosterone.

Women with an intact uterus must take combined HRT, replacing both oestrogen and progesterone, to prevent the lining of the womb thickening and thus reducing the risk of endometrial cancer of the womb. 

If a woman has had a hysterectomy then therapy can be oestrogen only. If she has already been on a cyclical combined course of therapy and reaches 54 years of age, or has had no periods for 12 months before starting HRT, she should start continuous combined HRT to prevent regular monthly bleeds. 

For how long can hormone replacement therapy be given and what are the risks?

The current recommendations are for the lowest dose for the shortest possible time to control symptoms. Women who do not have symptoms of menopause should not use HRT. All types of HRT are linked with an increase in the risk of breast cancer and some therapies increase the risk of cancer of the uterus. 

A 2019 study in over 100,000 women suggests that HRT causes 5% of all breast cancer case, which is higher than previously thought by experts. The study showed that 6.3% of women develop breast cancer between the ages of 50-70 years if they do not take and HRT. However, this risk of breast cancer is 8.3% in women taking HRT containing oestrogen and progesterone. In women taking progesterone only HRT, 7.7.% developed breast cancer.

There are some benefits of HRT including strengthening the bones, which reduces the risk of osteoporosis and broken bones, but this is only during the time of taking HRT. HRT also reduces the risk of getting bowel cancer but does not prevent heart disease, strokes or dementia. HRT should not be used for long-term protection of osteoporosis.

Women newly started on HRT should have their symptoms reviewed by their doctor after 3 months. Women who then remain on HRT should be reviewed at least every year by their doctor to see whether continuing on HRT is still the best treatment for them.

Can symptoms be prevented from returning after HRT is stopped?

It has been suggested that slowly reducing the therapy dose over a period of months may help reduce the return of flushes, but there is no scientific evidence for this. Unfortunately, the symptoms will return if they are going to, whether therapy is stopped gradually or suddenly. 

Active women may suffer fewer symptoms than inactive women, so regular exercise may help. Reducing alcohol and caffeine intake may help reduce hot flushes. Some prescription medications from the doctor such as clonidine and some antidepressants may also help.  

Herbal medicines may help in some cases, especially as they may contain small amounts of plant oestrogens - phyto-oestrogens. Their value has not been confirmed, and often the amounts contained are so low that they are unlikely to be effective. Black cohosh, red clover, dong quai, evening primrose and ginseng are among those that have been used, apparently with some success, but they should be taken in consultation with a GP because they may have a negative effect on other medication or may not be suitable for some women. In particular there have been concerns about black cohosh because of its potential for liver damage. There is limited evidence of the general effectiveness of complementary therapies which can also include acupuncture and other physical treatments. However, many women have found complementary medicine to be effective in relieving the symptoms and effects of menopause in individual cases.    


Last reviewed: Feb 2018