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22 AUGUST Save

Busting MHT myths

There are a lot of myths out there about the possible risks and benefits of menopausal hormone therapy (MHT). Patients often find it hard to know what, or who to believe.  

Here are some simple answers to some commonly asked questions about MHT. 

FALSE: MHT causes heart attacks

If you begin taking MHT within 10 years of your last period, it does not appear to increase your risk of heart attack or stroke.1,2

This idea spread after results from the Women’s Health Initiative (WHI) trial were released in 2002.

The WHI study was conducted to see if MHT could help prevent certain chronic diseases associated with ageing (such as cancer, cardiovascular disease and osteoporosis) in postmenopausal women.2

Results showed an increased risk of heart attack and stroke in the women who received estrogen plus progestin MHT. Women who took estrogen-only MHT did not have an increased risk of these conditions.2

However, the women in the WHI study had an average age of 63 years,2 which is many years older than the average age of menopause in Australia (51 years).3

Also, since the WHI study was published, further studies in younger women have shown that there is no significant increase in cardiovascular risk associated with starting MHT when taken for less than 10 years after menopause.1

FALSE: Estrogen causes breast cancer

Estrogen-alone MHT does not increase the risk of breast cancer.2 But it’s really important to discuss the risks and benefits of MHT, and to regularly reassess the need for treatment.3

Another result from the WHI study was that women who used estrogen plus progestin MHT had a small increased risk of breast cancer at 5 years. The women who took estrogen-only MHT did not show an increased risk of breast cancer.2

It’s important to know that the increased risk of breast cancer due to MHT is much smaller than the increased risk due to lifestyle factors such as a lack of regular exercise, weight gain and alcohol use.4

PARTLY TRUE:  MHT causes blood clots

Oral estrogen-only MHT is associated with a very small increased risk blood clots.2 Combination estrogen plus progestin therapy has a higher risk of causing blood clots.2  

Taking oral MHT can increase the risk of having a blood clot. However, the risk with estrogen-only MHT is much lower (2.5 in 1000 after 5 years of use) than the risk with estrogen plus progestin (5 in 1000 after 5 years of use) combined MHT.2,5

It’s important for women to talk to their doctor about the possible risks and benefits of different types of MHT.3

Also, keep in mind that other risk factors such as obesity, smoking, and not being active are also important risk factors for blood clots.2

FALSE: MHT causes weight gain

Menopausal weight gain is generally due to factors other than MHT.6   

It’s very common for women to gain weight during menopause, but research shows this is generally due to the hormonal changes that occur during ageing.6 MHT itself has not been linked to weight gain – in fact there is some evidence that MHT may help reduce the amount of fat accumulated around the abdomen during menopause.3,6

To avoid gaining excessive weight during menopause, women should try to eat a healthy diet and stay physically active. Keeping weight under control can also help to ease some menopausal symptoms.3,6  

FALSE: You can only take MHT for 5 years – then you have to stop

MHT may be taken for as long as necessary to alleviate menopausal symptoms.2,7 However, it’s important to regularly assess the need for treatment, including individual risks and benefits.2,7

MHT can be taken for as long as the benefits of alleviating menopausal symptoms outweigh the potential risks of ongoing treatment.2,7

Australian medical authorities recommend that MHT is taken for a maximum of about 5 years. This is because some of the risks of taking MHT increase over time. For example, the risk of developing breast cancer with combined MHT appears to increase with use.2 However, some women with troublesome menopausal symptoms may need to use MHT for longer than 5 years, and they can do so if recommended and with regular monitoring by their doctor.2

FALSE: ‘Bioidentical’ hormones are a safe alternative to MHT

‘Bioidentical’ hormones have not been shown to be safe or effective for treating menopausal symptoms.2,8

Bioidentical hormones are synthesised to resemble the hormones produced by the body. They are often described as being ‘natural’, but they are not really any more natural than the hormones contained in prescription MHT products. They often contain the same form of hormones, and these hormones are processed in the body in the same way as regular MHT. Bioidentical hormones are usually supplied by compounding pharmacists as skin creams or lozenges that are placed between the cheek and gum.8

Bioidentical hormone products are not recommended because they:8

  • Are not subject to the same stringent quality standards required for prescription medicines
  • have not undergone the same rigorous scientific testing as prescription MHT, so they have not been proven to be effective and safe.
  • may contain abnormally high levels of hormones that make them unsafe for women.
  • are often more expensive than prescription MHT.   


PBS Information: This product is not available on the PBS.

Before prescribing, please review Product Information available here.



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  1. Boardman HMP et al. Cochrane Database Syst Rev. 2015;3:CD002229.

  2. Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) Menopausal Hormone Therapy Advice. (C-Gyn 16). July 2015.

  3. Jean Hailes. Menopause management. Available at: https://jeanhailes.org.au/health-a-z/menopause/menopause-management (Accessed October 2016).

  4. Reid RL. J Soc Obstet Gynaecol Can. 2000;22:677–81.

  5. Manson JE, Kaunitz AM. N Engl J Med 2016;374(9):803–6.

  6. Davis SR et al. Climacteric. 2012;15(5):419–29.

  7. De Villiers T. et al. Global Consensus Statement on MHT. Climacteric 2013;16:203–4.

  8. Australasian Menopause Society. Bioidentical hormones for menopausal symptoms Available at: https://www.menopause.org.au/for-women/information-sheets/34-bioidentical-hormones-for-menopausal-symptoms (Accessed October 2016).

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