HRT Benefits & Risks Explained

We believe the management of perimenopause and menopause should be a personal informed choice based on current best-available evidence. Some people cannot take hormone replacement therapy (HRT), or choose not to, but many are also needlessly denied the option of taking HRT when it would have been beneficial to them.

Here, we aim to summarise what we currently know about body-identical hormone replacement therapy risks and benefits.

Is hormone replacement therapy safe?

Hormone replacement therapy is considered safe and effective for most women in perimenopause and menopause. In the majority of cases, the disadvantages of HRT i.e. side effects and minimally increased risks, are heavily outweighed by the benefits of HRT therapy. Any serious risks of HRT are very rare.

However, the safety of HRT is dependent on:

Age: Taking HRT before the age of 60 is very safe for most women
Body Mass Index: Women with higher BMIs ( ‘body mass index’ - a measure of height to weight ratio) can be at increased risk of some side effects from certain types of HRT
Medical history: Certain conditions such as significant liver disease, risk factors for stroke such as certain types of migraine and breast, ovarian or womb cancer, can influence the suitability of HRT

HRT risks

As with any medication which has an action of the body, HRT carries some risks. However, it is important to understand these risks in context and any other factors that increase them.

Breast cancer

The risk of breast cancer is often the biggest concern for women when considering starting HRT. At this point, evidence suggests that when it comes to HRT and breast cancer, medication probably very slightly increases the risk of breast cancer when taking combined HRT (both oestrogen and progestogen) started during average menopausal age. This risk appears to be related to the type of progestogen used in HRT, with body-identical, micronised progesterone and dydrogesterone (a synthetic progestogen) appearing to have the lowest risk. The small additional risk appears to be associated with longer duration of treatment.

It is important to understand that the small potential increased risk of developing breast cancer in association with combined HRT use, equates to around five extra breast cancer cases in every 1000 women who take combined HRT for five years. This is thought to be less than the increased risk associated with drinking a couple of glasses of wine a night, having a sedentary lifestyle or living with obesity.

If you are diagnosed with breast cancer when/after taking HRT there is no evidence that this will lead to an increased risk of dying. That said, seeing someone close suffer with breast cancer may be enough for someone to decide they want to take no increased risk at all. This is perfectly justified and, again, comes down to personal choice.

Women who have had a hysterectomy and are taking oestrogen-only HRT do not appear to have any significantly increased risk of developing breast cancer, with some previous studies actually suggesting a decrease in risk. However, more studies are needed before we can confidently confirm this.

Importantly, there is no increased risk of developing breast cancer secondary to HRT use if you are prescribed this for POI (Premature Ovarian Insufficiency) or early menopause. The breast cancer risk only becomes relevant after the average age of natural menopause (~ 51 years).

Endometrial and ovarian cancer

Oestrogen-only HRT increases the risks of developing endometrial (womb) cancer. The risk increases the longer HRT is used and may remain elevated for several years even once medication is stopped. This is why oestrogen only HRT is only recommended to women who have had a hysterectomy. Women who still have their womb are given combined HRT (oestrogen and progesterone) preventing overgrowth or changes to the womb lining. Combined HRT has not been shown to increase the risk of endometrial ( womb) cancer provided that the amount of oestrogen given is adequately opposed by the dose of progesterone.

Both oestrogen-only and combined HRT may very slightly increase the risk of developing certain types of ovarian cancer. There is very limited data to draw on but one study summarising the data of several observational studies found an increase of 1 extra case per 5000 women per year. Once medication is stopped, the risks go back down to personal background risk.

Blood clots

HRT tablets can increase the risk of blood clots, although the risk is still very low. The average likelihood of a blood clot, including a deep vein thrombosis or pulmonary embolism, is about 1 in every 1000 adults per year. For women taking oral HRT, studies suggest this risk is doubled to 2 in 1000 Being older or overweight increases the risk further.

Patch, spray or gel form HRT does not appear to increase the risk of blood clots. This is because oestrogen is safer when absorbed through the skin. If you are already at a higher risk of blood clots, you’ll normally be advised to take one of these types of HRT rather than tablets.

Stroke

Around 80% of strokes are caused by a blockage, with the most common being a blood clot. Oral HRT can slightly increase the risk of stroke, especially within the first six months of starting treatment, because it can increase the risk of blood clots and high blood pressure. Low-dose HRT patches, gel and spray do not appear to increase the risk of stroke.

Furthermore, women who experience migraine with aura have a slightly higher baseline risk of stroke. For this reason women who have a history of migraine with aura are more likely to be recommended HRT preparations with gel, patch or spray rather than a combined oral HRT preparation. These will not add any extra risk.

Gallbladder disease

Taking HRT can very slightly increase the risk of gallbladder disease. However, the risks are significantly lower when taking transdermal HRT (patches, gel or spray) compared to tablets.

Among women using HRT tablets, body-identical formats (i.e. oestradiol) there are lower risk than the older synthetic types of oestrogen.

For the majority of women the benefits significantly outweigh the risks and women with a history of gallbladder disease can still be prescribed HRT.

Allergic reaction

In extremely rare cases, it’s possible to have a severe allergic reaction (anaphylaxis) to continuous combined HRT that requires immediate medical attention. This risk exists with any medication including ones bought on the shelves. Signs of a severe allergic reaction include:

Swelling of the lips, mouth, through and/or tongue
Rapid breathing or struggling for breath
Throat tightness
Difficulty swallowing
Blue, grey or pale skin, tongue and lips
Confusion, dizziness or drowsiness
A rash that is swollen, raised, itchy, bruised or peeling
Fainting

Dementia

Evidence on the risk of dementia when taking HRT is conflicting. A study in 2021 found that both old and newer body-identical forms of HRT reduce the risk of diseases that cause dementia. Whereas another study of over 55,000 women found that HRT increases the risk of dementia.

Some of the confusion may lie in the fact that menopause can impact cognitive function, causing brain fog, memory problems and difficulty focusing, which are also symptoms of dementia.

Presently when all evidence is taken into account, we consider the impact of HRT neutral on all round dementia risk. HRT may have a protective effect on reducing the risk of certain types of vascular dementia in the same way they positively impact the cardiovascular system but again there is more research needed to fully understand this link.

Fibroids

The link between HRT and fibroids is not totally clear. HRT does not appear to increase the risk of developing fibroids but may increase the likelihood of existing fibroids growing.

One study that compared women who were and were not taking HRT found that fibroid volume increased for both after one year. Significant fibroid growth continued in the second year for HRT users but not non-users. However, in the third year, volumes declined.

It is important that a history of fibroids is considered when prescribing HRT but many women with fibroids take HRT successfully without any complications.

Advantages of hormone replacement therapy

For the vast majority of women, starting HRT in perimenopause (i.e. when symptoms start while still having periods/cycles) or within ten years of the final period (post-menopause), offers many health advantages.

Relieving menopause symptoms

One of the biggest benefits of HRT is that it alleviates distressing menopause symptoms including:

Hot flushes
Night sweats
Brain fog
Joint pain
Mood swings
Vaginal dryness

Preventing osteoporosis

Declining oestrogen levels during perimenopause and menopause can change your bone density and cause them to break down more quickly than they can regenerate. Up to 20% of bone loss can happen during menopause and postmenopause, and osteoporosis affects 1 in 10 women over the age of 60. HRT replenishes oestrogen in the body which can help prevent osteoporosis and bone fractures. HRT is also a licensed treatment for women who develop HRT under the age of 60.

Reducing the risk of heart disease and metabolic conditions

A study has shown that short-term HRT (2-3 years) use can reduce cardiovascular disease mortality by 30%. Other research found that women who started HRT within 10 years of menopause had a 24% lower risk of heart disease events than women who took a placebo.

Furthermore, HRT can reduce the risk of metabolic conditions including glucose intolerance, low levels of high-density lipoprotein cholesterol, high levels of triglycerides, obesity, and hypertension.

HRT is not licensed or recommended as of yet in guidelines as a preventative medication but for women who choose to take HRT to support their wellbeing or relieve symptoms, evidence demonstrates these additional benefits.

Maintaining muscle mass

From age 30-50, adults lose between 3% and 8% of their muscle mass per decade and by 50, this speeds up to between 5% and 10%. The drop in oestrogen during menopause appears to accelerate this.

However, those who use oestrogen-based HRT lose less muscle mass and notice that it can also improve muscle function, alongside regular exercise.

Reducing overall mortality rates

In some studies, HRT has also been shown to reduce overall death (mortality) rates. This is especially relevant for anyone who has premature ovarian insufficiency (POI), or early and/or surgical menopause. In these cases, unless there is a history of hormone-dependent cancer, HRT is strongly recommended to protect long-term health until at least the age of natural menopause (~ 51 years).

Some women are incorrectly told that if they have a history of blood clots, migraine, or hormone-sensitive conditions such as endometriosis or epilepsy, they cannot take HRT. Although these conditions can make HRT prescription a little more complicated, and there can be small risks associated with possible worsening of their underlying condition, HRT can usually be safely prescribed following discussion with an accredited menopause specialist and appropriate monitoring.

We still have much to learn in the field of female hormonal health and there are pros and cons of HRT. However, for most women, the overall risks of HRT are very small, and the benefits of HRT can be life-changing.

Knowing which doctor to consult for menopause symptoms and treatments can make a world of difference to your well-being. At Menopause Care we have a team of specialists with the knowledge and experience to help. If you’d like to find out more about HRT and explore what treatment is recommended for your personal circumstances, book a consultation with a menopause doctor.

DisclaimerAt Menopause Care, we ensure that everything you read in our blog is medically reviewed and approved. However, the information provided is not meant to replace professional medical advice, diagnosis, or treatment. It should not be relied upon for specific medical advice.

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