What is HRT?

Hormone replacement therapy (or HRT) (also known as menopausal hormone therapy; MHT) is the replacement of female sex hormones oestrogen and progesterone in women to control symptoms of the menopause.

What is hormone replacement therapy?

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 a sense of wellbeing and health. Oestrogen is also very important to maintain strong, healthy bones and help prevent osteoporosis.
In a healthy woman of childbearing age, hormones are produced and released from the pituitary gland in the brain, including LH (luteinizing hormone) and FSH (follicle stimulating hormone). LH and FSH encourage the ovaries to produce an egg (ovum). At the same time, oestrogen and progesterone are released from the ovaries. These hormones prepare the endometrium (womb) for a pregnancy. If pregnancy does not occur, these hormone levels fall and the woman will have a period.

After the menopause, the ovaries no longer respond to stimulation by the hormones from the pituitary gland and stop producing eggs and oestrogen. Due to low oestrogen, progesterone and inhibin levels, there is a loss of negative feedback on the hypothalamus and pituitary gland, such that FSH (and LH) are markedly increased.

The menopause means that a woman can no longer become pregnant. In the approach to menopause, her periods either stop abruptly, or they may decrease more gradually over months, or even years. Irregular periods in the lead up to menopause is termed the ‘climacteric’.

‘Peri-menopause’ refers to the time within 12 months of the last menstrual period, whereas Post-menopause refers to the time thereafter.

At this time symptoms may appear, including:
- Hot flushes
- Night sweats
- Insomnia
- Palpitations
- Mood changes
- Vaginal dryness and painful intercourse
- Mild skin changes such as dryness and loss of elasticity
- Joint and muscle stiffness
- Changes in concentration levels

Treating women with HRT replaces the hormones that are no longer being released from the ovary and can relieve some of the symptoms associated with the menopause, enabling the woman to feel better, both physically and mentally.

When can hormone replacement therapy be used?

Most women have their menopause between 45-55 years of age, with the average age being 51. Some women go into an early menopause before they are 40 yrs old, termed premature ovarian insufficiency (POI).

Most women are postmenopausal by the age of 54 years. The symptoms of the menopause usually last between one and five years and vary between individuals. Less commonly women will still experience hot flushes at 10 years after their menopause began, whereas others may not have hot flushes at all. Some symptoms can gradually disappear without any treatment, but for others, symptoms can be so severe that HRT treatment may need to be for a prolonged duration.

Women who commence the menopause early before the age of 40 years have ‘premature ovarian insufficiency’ (POI). Other triggers that are associated with earlier menopause, including underlying medical conditions (e.g. Addison’s disease), autoimmune diseases, some infections, or previous cancer treatments such as certain types of chemotherapy or radiotherapy to the pelvic area.

What types of therapy are there?

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

• Oestrogen only; suitable for women who do not have a uterus (womb).
• Cyclical combined – which is both 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 thickening of the lining of the womb and therefore reduce the risk of endometrial cancer of the womb. If a woman has had a hysterectomy (removal of the womb) then HRT can be oestrogen only.

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, although this is very small (~0.01%), and can increase the risk of cancer of the uterus if progesterone is not also used. For some women who take combined HRT tablets, there may be an increased risk of developing a clot or having a stroke: this risk is much reduced if the HRT is in the form of a patch or a gel.

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

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, discuss their signs, symptoms and wellbeing, and 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. Dietary changes can also help with symptoms, such as increasing foods rich in calcium and vitamin D, and reducing sugar intake. Some prescription medications from the doctor such as clonidine may help with hot flushes. Some antidepressants may also help the hot flushes and night sweats, although NICE guidelines state that there is no evidence that antidepressants will help with low mood.

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, St. John’s Wort 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 the use of 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, aromatherapy 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. Cognitive behavioural therapy (CBT) has also been shown to help with menopausal symptoms.

NB – HRT is NOT the same as transgender hormone therapy, or cross sex hormone therapy, where sex hormones and other hormone medications are administered for transgender individuals.

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Last reviewed: May 2021