Hormone Replacement Therapy, or HRT, is the most widely used treatment for menopausal symptoms, and is considered by many to be the most effective. The aim of HRT, as its name would suggest, is to replace the hormone that the body ceases to produce during the menopause, namely oestrogen.

All of the common symptoms of the menopause are associated with a decrease of the body’s production of oestrogen, including night sweats, vaginal dryness, headaches, depression, reduced sex drive, and the infamous hot flushes!

While the benefits of HRT are widely recognized, its unwanted side effects are the cause of much controversy, with some studies claiming it can increase the risk of cancer and heart disease. But first, let’s take a look at exactly what HRT is and how it works.

The low-down on HRT

HRTs today come in all shapes and sizes, each designed to offer as wide a choice as possible to the menopausal woman. However, there is not only choice in the type and dose of hormones available, there is also choice in how these hormones are introduced to the body – or what doctors call “the route of delivery”. There are three main routes, and each will be appropriate for different women:

  • Via the mouth as a tablet – this is the most common form of HRT.
  • ‘Transdermal’ (through the skin) methods are less common but still very popular. They can take the form of an adhesive patch, a gel, or a nasal spray.
  • Finally as an implant injected beneath the skin to provide long-term effect.

It is also possible – particularly for vaginal symptoms – to take HRT as a pessary inserted within the vagina itself to provide very “local” relief, or for greater effect as a soft ring inserted within the vagina for 28 days.

Which HRT?

The type of HRT most suited to a woman will depend on a variety of factors, including her stage in the menopausal process, and whether or not she has had a hysterectomy. One in five British women will have had a hysterectomy by the time they are 55, so this is an important factor for many. Most forms of HRT combine different amounts of the hormones oestrogen and progesterone (manufactured progesterone is called progestogen in the UK and progestin in the US).

There are over 50 different combinations of HRT currently available. Most women will make their choice over whether to take HRT, and which form, with the help of their GP. Here is a summary of the main forms:

Oestrogen alone

The core ingredient of all forms of HRT is oestrogen. Oestrogen relieves hot flushes, prevents vaginal symptoms and maintains bone strength. The best HRT for women who have had a total hysterectomy, where the whole womb including its neck (cervix) has been removed, is oestrogen alone. Combined HRT (oestrogen plus progestogen) offers no benefits for these women and may increase their risk of breast cancer.

However, in women who have had a partial hysterectomy (with cervix intact), some womb lining (endometrium) may still remain, and for those who have not had a hysterectomy, an oestrogen-alone HRT can affect the lining of the womb (endometrium), leading to excess growth and possibly cancer. In these cases a second hormone is also prescribed (progestogen) to counteract the effects of oestrogen. For women with endometriosis a continuous combined HRT is recommended (see below).

Oestrogen and progestogen

All women who have not had a hysterectomy will be advised to take ‘combined HRT’ which contains oestrogen and progestogen. Women who have had an endometrial ablation (an operation to remove the lining of the womb which is often performed for very heavy periods) should receive progestogen in case any part of the endometrium is left.

This is available in the form of either a tablet or a patch. In this way they ensure they receive the benefits of oestrogen but the uterus is also protected from harmful changes.

Early forms of HRT simulated a menstruation cycle by adding progestogen in tablet form for 12 days a month. This meant that in the days following this course the user would have a ‘bleed’ similar to that of a natural cycle. This form of ‘cyclical’ or ‘sequential’ HRT is still used in peri-menopausal women and during the first year or two after the menopause.

Forms of hormone replacement that give continuous progestogen with the oestrogen have been developed to avoid bleeding altogether. This method is called ‘continuous combined HRT’ and is thought to reduce the risk of endometrial cancer. One year after the menopause has occurred, many women prefer to switch to continuous combined HRT. However, it is not always easy for doctors to decide when a woman has reached this stage. Strictly speaking, a woman is considered to be postmenopausal 12 months after her last period, but this can be difficult to determine especially for women who start to use HRT before their periods stop.

This table shows how the timing of progestogen will affect bleeding:

Progestogen Intake


10-14 days in a monthMonthly bleeds
14 days every 13 weeksBleeds every 3 months
ContinuousNo bleeds


The first “bleed-free” HRT contained a man-made hormone known as Tibolone which, when taken every day, had the combined effects of oestrogen and progestogen. Studies have shown that Tibolone relieves all menopausal symptoms, prevents bone loss, and even improves interest in sex. Tibolone, like other continuous therapies, is normally prescribed at least 12 months after the last menstrual period, so many women switch to these continuous types after taking a sequential HRT.

The latest developments

While sequential HRTs aimed to cause bleeding once a month, and continuous HRTs to avoid bleeding altogether, a new development has tried to strike a medium by inducing a withdrawal bleeding every three months. This is done by adding progestogen to daily oestrogen for just 14 days every 13 weeks, which means that the uterus is still protected.

However, the most notable recent innovation has been seen in lowering the dose of hormones – particularly oestrogen – in combined HRTs. The new lower dose varieties aim to reduce the incidence of side effects while maintaining symptom relief and bone strength.

Side effects associated with HRT

As with any drug, there are known short-term and usually mild side effects from HRT which may trouble some women, especially in the first few months of use. These may include breast tenderness, leg cramps, nausea, bloatedness, irritability and depression. These side effects are all related to oestrogen or progestogen, and may be overcome by a change of dosage or ingredients in the HRT prescribed. For example, recent studies suggest that Tibolone, unlike other HRTs, does not cause breast tenderness.

Irregular bleeding or spotting can occur during the first 4-6 months of taking continuous combined HRT or Tibolone, and is not a cause for alarm. However, you should consult your doctor if you get heavy (rather than light) bleeding, if it lasts for more than six months, or if bleeding starts suddenly after some time without bleeding. Irregular bleeding may sometimes be improved by changing to an HRT with a higher progestogen dose.

Help in knowing whether you are postmenopausal

Choosing an HRT is difficult enough, and can be even more complicated if you are unsure whether you are still going through the menopause or whether that time is assigned to the past. These guidelines might help you to recognize the end of the menopause.

  • Age: 80% of women are postmenopausal by the age of 54
  • If your periods stopped at an early stage
  • If blood tests have showed raised levels of Follicle Stimulating Hormone (FSH)

Treating local symptoms without raising hormone levels throughout the body

Some women do not wish to use, or cannot take, systemic HRT in any form which raises hormone levels throughout the body, but they still appreciate the relief of symptoms such as dry vagina and urinary problems. In this case, oestrogens can be given locally to the vagina in the form of a low dose cream, pessary, tablet or ring. These preparations raise local hormone levels but do not affect the whole body. Low doses of natural rather than synthetic oestrogens (e.g. oestriol or oestradiol) are best for this form of treatment. Progestogen is not needed, since these local doses of oestrogen do not affect the endometrium. Synthetic oestrogens should be avoided because they can enter the blood stream from the vagina. Local treatments often need to be taken on a long-term basis as symptoms often return when treatment is stopped.

The HRT controversy

Concerns over increased risks of breast cancer, ovarian cancer and heart disease remain controversial and are the object of much scientific discussion. You can read more about this in our leaflet HRT: What you should know about the benefits and risks. If you are concerned about taking HRT you should talk to your healthcare practitioner, or alternatively phone the WHC Nurse Advice Line.

The next step

It is important to remember that the choice of whether or not to take HRT is in your hands. This factsheet aims to help you understand all the HRT-related options available to you. However, there are other ways of dealing with menopausal symptoms that can be used either alongside HRT or instead of it. To read more about these, please see our factsheet on Complementary/alternative therapies for menopausal women.

Related WHC factsheets

Useful contacts

The National Osteoporosis Society (NOS)

0845 130 3076 (Monday to Friday 10am to 4pm)

Email: info@nos.org.uk

Website: www.nos.org.uk

Menopause Matters

Website: www.menopausematters.co.uk

The Hysterectomy Association

0871 7811141

Email: info@hysterectomy-association.org.uk

Website: www.hysterectomy-association.org.uk

This factsheet has been produced by Women’s Health Concern and reviewed by members of our Medical Advisory Panel. It is for your information and advice and should be used in consultation with your own medical practitioner.

Updated: March 2010

Women’s Health Concern is an independent charity and receives no government funding.

Registered Charity No. 279651

Email advice: advice@womens-health-concern.org

Website: www.womens-health-concern.org