Benefits and risks of taking HRT

The risk/benefit balance of HRT varies between women and for each woman, from year to year depending on presence or not of symptoms, other medical history and number of years that HRT has been taken.

Generally, if you become menopausal early (before age 45) or prematurely, POI, (before age 40), the benefits of taking HRT up to at least age 50 far outweigh the risks.

If you are under 60 and having menopausal symptoms, or have risk for osteoporosis, the benefits also outweigh the risks.

There are no arbitrary limits as to how long HRT can be taken, it is up to each woman to balance the risks against the benefits for her. Some women may not need HRT at all, or may take it for a few years only, while others continue to take HRT for many years since it continues to provide significant benefits for them.

Every woman should be supported to make an informed choice about their use of HRT.

Currently the evidence we have is:

Benefit of HRT:

  • It is the most effective treatment for the relief of menopausal symptoms
  • Reduced risk of coronary heart disease when oestrogen is started early (within 10 years of menopause)
  • Improved bone mineral density with reduced fracture risk while it is being taken

Risks of HRT:

Risks associated with HRT include association with increased risks of breast cancer (with long duration HRT), blood clot and, if HRT is started many years after the menopause, possibly cardiovascular disease. For the majority of women who use HRT under the age of 60, and for many beyond that age, the benefits of HRT outweigh any risks.

Cardiovascular disease:

  • Studies show that there is a reduced risk of coronary heart disease when oestrogen is started early (within 10 years of menopause). 
  • Taking an oral tablet of oestrogen is associated with a small increase in risk of stroke. The risk of stroke in women under 60 years is very low, so the increased risk is small (1 extra woman per 1000 using HRT). 

Blood clot / venous thromboembolism

  • Taking an oral tablet of oestrogen causes a small increase in risk of blood clot. The greatest risk is within the 1st year of use and is most relevant to women who have other risk factors, like a BMI > 30.
  • If there is a past or family history of blood clot or an inherited thrombophilia, appropriate investigations may be needed before prescribing. For some who are particularly at risk of blood clot, including women who have a Body Mass Index greater than 30, the pros and cons of use of HRT should be discussed and if using HRT, taking it as a transdermal oestrogen like a gel, spray or patch with a progestogen with low clot risk should be considered, since there is strong evidence that transdermal estrogen does not increase risk of blood clot in healthy women using moderate doses of oestrogen.

Type 2 Diabetes

  • There is no increased risk of developing type 2 diabetes with any type of HRT. 
  • Some of the progestogens taken in HRT can affect insulin sensitivity, we will consider this when prescribing

Breast cancer

  • Current opinion is that HRT taken for less than 5 years does not significantly increase the risk of breast cancer but studies have shown that after 5 years of use, there is an association with a small increased risk. Once HRT has been stopped, the risk returns back to baseline.
  • It seems very likely that different types of HRT are associated with different risk, oestrogen appears to increase the risk very little while there appears to be a small increased risk of cancer promotion with long term use of oestrogen combined with progestogen (combined HRT).
  • Different data shows slightly different results:
    • The NICE guideline on Diagnosis and Management of Menopause concluded that for every 1000 women aged 50 to 59, combined HRT may be associated with an extra 5 cases of breast cancer over 7.5 years, with no extra cases for women taking estrogen only. (NICE guideline). 
    • More recent analysis of risk with different types of HRT is shown at MHRA 1 and MHRA 2  
    • E3N observational studies have been done which found no increased risk of breast cancer over five years with the use of oestradiol and micronised progesterone as HRT.
  • Lifestyle factors play a role in cancer risk, this link takes you to a chart which is very helpful to show the comparison of lifestyle risk factors vs taking HRT
  • If HRT is started at a young age because of premature ovarian insufficiency, POI, then the use of HRT up to the age of 50 is unlikely to increase breast cancer risk any more than in women who continue to have periods up to the age of 50. Additional risk from HRT only applies if it is then taken for more than 5 years after 50.

Ovarian cancer

  • There continues to be uncertainty about the possibility of increased risk of ovarian cancer with use of HRT. With 5 years of HRT use, there could be 1 additional ovarian cancer per 1000 users and 1 additional death per 1700 women who use HRT.

Dementia

  • More studies are needed in this area. Current evidence suggests that HRT is unlikely to increase the risk of dementia or to have a detrimental effect on cognitive function in women initiating HRT before the age of 65.

Endometrial cancer

  • Oestrogen only therapy given to women with an intact uterus increases the risk of endometrial hyperplasia (thickening of the lining of the uterus) and eventually endometrial cancer.
  • Daily oestrogen combined with progestogen given for 10 to 14 days per month, giving a monthly bleed is called sequential sHRT. Taking progestogen cyclically in sHRT reduces the risk of endometrial cancer but does not eliminate it. If you are taking  sequential combined HRT at the age of 45 or above, within 5 years of taking it this way we would change the way you take HRT to a continuous combined ccHRT. This means you would take you progestogen daily, not cyclically. If you have a 52mg LNG IUD like a Mirena this is like continuous combined HRT. Sequential combined HRT, given for more than 5 years, does increase the risk of endometrial cancer by a small amount. No increased risk appears to apply to oestrogen combined with daily progestogen (continuous combined or period-free HRT).
  • It is important to report any unscheduled bleeding on HRT to your Dr.
  • It is important that your oestrogen and progestogen dose is balanced, you Dr will look at your risk factors for endometrial cancer and your dose of oestrogen in your HRT when deciding what dose of progestogen to prescribe.
  • It is important to take your progestogen as prescribed.

There are medical conditions which can be affected by hormonal change and HRT such as migraine, epilepsy and thyroid disease. Please discuss this with your Dr when you are considering HRT so the safest and correct preparation is prescribed to you.

If you have any questions about benefit and risk please talk with us. 

Dr Carys Sonnenberg Rowena Health – this information is provided to you, to the best of our knowledge using links to trusted sources to help you understand the current evidence. There is of course a great deal of information, and risk and benefit of any medication is individual to you, and must be discussed with your prescribing Dr, who has responsibility for your care and knows your medical history. For our patients we will individualise the advice given – July 2024

Other websites to refer to:

Women’s health concern fact sheets

Menopause Matters

Rock my Menopause

British Menopause Society tools for clinicians – at Rowena Health we support GP’s in their learning, this link takes you to articles which will support the education of your GP

International Menopause Society advice for women

This information is based upon NICE guidance, the British Menopause Society and Menopause Matters

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