What is HRT (Hormone Replacement Therapy)?

What is HRT?

This is the third in our series on Menopause. Check out our other articles on HRT to gain a deeper perspective on its role in menopause support:

The Link Between Breast Cancer and HRT

Alternatives to HRT (Hormone Replacement Therapy)

Hormone Replacement Therapy: HRT

Hormone Replacement Therapy, or HRT, is a group of hormonal medicines used to replace dissipating female hormones and treat menopausal symptoms. The hormones are oestrogen and progestogen, and sometimes testosterone.

Menopausal symptoms are caused by lowering hormone levels, brought on with age. Common symptoms include hot flushes, night sweats, low mood and mood swings, urinary urgency, trouble sleeping (insomnia), mild depression, irritability, anxiety, and irregular periods that lead to the end of the menstrual cycle. Vaginal symptoms include itching, burning, discomfort, painful intercourse, and vaginal dryness.

There are different ways HRT can be taken with different combinations of hormones, all of which are tailored to suit each individual woman. For example, some medications will contain oestrogen only, and others will contain a combination of oestrogen and progestogen. The Mirena Coil (LNG-IUS) can be used for the progestogen component of HRT, which is ideal if a woman still requires contraception. Testosterone is usually given separately.

Oestrogen and HRT

Let's start with oestrogen – this hormone is the main part of HRT and is given to reduce or stop menopausal symptoms to make you feel better. Each HRT dose can be given in tablet form, topical gel, spray, or skin patch. Usually, the oestrogen in the medication is oestradiol. This closely matches the oestrogen created in your body and works in a similar way, called ‘bioidentical' or ‘body identical'.

Sometimes the medications contain conjugated oestrogens, which is a mix of oestrogens. These don't match the ones created in your body but still work to combat menopause symptoms in a similar way. These are not used as much anymore in the UK.

When you take HRT, you will take oestrogen every day. A tablet is often tried first, but this can depend on individual preference, medical history, and family history. For example, if you have had a blood clot or have a family history of blood clots such as DVT (deep vein thrombosis), you will need a patch or a gel as these do not increase the risk of having a blood clot, whilst taking a tablet can increase the health risks slightly.

Taking oestrogen on its own can cause the womb lining to thicken and, after a period of time, could increase the risk of womb cancer. To prevent this, progestogens are given alongside.

If you have had a hysterectomy (surgical removal of the womb), you will need oestrogen-only HRT.

The lowest effective dose possible is used to relieve symptoms when using HRT. The dose can be steadily increased if little or no benefit is experienced. You are usually recommended to take HRT for at least three months to gain maximum benefit. This can be reviewed after the initial three months trial period. Sometimes the route in which HRT is given may be changed, for example, from a tablet to a patch, or vaginal creams, due to difficulties in absorption.

Progestogen and HRT

If you have a womb (i.e. have not had a hysterectomy), you must take progestogen alongside oestrogen. Taking oestrogen on its own can cause the womb lining to thicken and, after a period of time, could increase the risk of womb cancer. To prevent this, progestogens are given alongside. Progesterone is a natural hormone, and some HRT contains micronized progesterone, mimicking the one our body makes.

If you still have periods or 12 months haven't passed since your last period (perimenopausal), you will be prescribed 'sequential or cyclical' HRT. Oestrogen is given for the first two weeks, followed by a combination of oestrogen and progestogen for the next two weeks. You can expect a monthly withdrawal bleed which usually lasts 3–6 days, either towards the end of the combination of the two hormones or at the start of a new cycle of HRT. After a few months of taking this combination of HRT, you should start to predict when you will have a bleed. Some unscheduled bleeding can be expected in the first few months of starting this type of HRT.

If you have not had a period for over 12 months (post-menopausal), you will usually be given 'continuous combined' HRT. This is where both oestrogen and progestogens are given together every day. This type of HRT should not give you a monthly bleed; however, it is important to know that you may experience some bleeding within the first 3-6 months of taking this kind of HRT.

Many women choose to have a Mirena coil inserted as their progestogen component of HRT, especially if they still require contraception. Some women may already have the Mirena coil; if it has not been in place for more than five years, then oestrogen can be added alongside it. The Mirena coil must be changed after five years if used as part of HRT.

Testosterone and HRT

Around 100–400mcg of testosterone per day is produced in young women and reduces as we age, usually until over 40. Testosterone is important for sexual arousal and orgasm, so when the levels decrease, some women can feel less interested in sex and have difficulty being aroused. Loss of testosterone can also impact a woman's energy levels. Some women report having less energy and being unmotivated to participate in their usual activities.

Testosterone is not routinely given as part of HRT. Replacing oestrogen can help with the loss of libido (one of many physical and emotional symptoms); testosterone is never given on its own. It will only be considered when other potential causes of low libido have been excluded and when HRT has not helped.

Testosterone is given in a topical gel applied to the skin. It is not licensed for use in women but can be used off licence in the UK. Regular blood tests are usually required once established on testosterone, and it can take three to six months before you see any benefits that relieve menopausal symptoms. Unfortunately, testosterone does not work for everyone.

Pros and Cons of HRT

As with taking any medicine, there are potential risks alongside the benefits (ultimately, to relieve menopause symptoms) of using HRT. The risks and benefits should always be discussed, as well as considering your medical history to see what is right for you.

Of those risks, HRT treatments can cause side effects, which may include headaches, feeling sick, breast tenderness, and vaginal bleeding, but for most women, the treatments provide little problem, and the benefits far outweigh any risks.

Benefits and risks will vary from woman to woman. These are strongly linked to diet, lifestyle, past medical and family history. For most women, the short-term benefits outweigh the risks of taking HRT. The safety of HRT largely depends on a woman's age: if HRT is started under 60 in healthy women, then there are no real concerns, especially when HRT is started within a few years of menopause.

Venous Thrombo-embolism or blood clot (VTE): There is a small increased risk of having a VTE if taking a tablet but not with a patch/spray or gel HRT (transdermal). You should be offered transdermal HRT if you are at high risk for VTE, including those with Body Mass Index over 30.
Cardiovascular disease: There is no increased risk when HRT is started under 60. There appears to be a small increased risk of stroke within the first year of taking a tablet but no increased risk with transdermal HRT. Studies have shown that starting HRT before age 60, or within ten years of menopause, may protect the heart and reduce the risk of heart disease.
Diabetes: HRT does not affect the risk of developing diabetes.
Breast cancer: HRT does not affect your risk of having breast cancer. Oestrogen-only HRT is associated with little or no increased risk of breast cancer.

HRT with both oestrogen and progestogen is associated with a small increased risk of breast cancer if taken for five years or more. The risk of breast cancer reduces after stopping HRT. However, you are at greater risk of breast cancer if you are overweight and drink more than 14 units of alcohol per week than by using HRT.