Menopausal hormone therapy: what it's all about

Menopausal hormone therapy (MHT) is the use of hormones to relieve symptoms of perimenopause and menopause and/or reduce the risk of osteoporosis. It used to be called hormone replacement therapy (HRT), but the name was changed to differentiate it from hormone replacement for endocrine abnormalities such as growth hormone deficiency — and really, ‘hormone therapy’ is a better name because the lower oestrogen of menopause is normal, not a deficiency. 

When it comes to hormone therapy, the word ‘type’ can actually refer to four entirely separate questions: 

1. The hormone itself (whether it’s an oestrogen, progestogen [a medication that produces similar effects to the natural hormone progesterone] or testosterone)
2. whether that hormone is body-identical or not, 
3. conventional versus compounded formulas, and 
4. the route of administration (pill, patch, etc). 

So, if you’re wondering which ‘type’ of hormone therapy to choose, you need to begin by understanding those four questions. Let’s look at each in turn.

Oestrogen, Progestogen and Testosterone

Oestrogen 

Oestrogen is the hormone most people think of for hormone therapy and for good reason. It’s the hormone best studied for the treatment of hot flushes, vaginal dryness and other menopausal symptoms — as well as for the prevention of osteoporosis in some women.  

There are different available forms of oestrogen, including:  

1. estradiol
2. estriol
3. estrone
4. and conjugated oestrogens  

All can be accurately described as ‘oestrogen’ because (unlike progesterone) oestrogen is a generic term – it’s the name for this group of hormones rather than the name for a specific hormone. 

The side effects and risks of oestrogens vary depending on:  

• form (e.g., oestradiol versus conjugated oestrogens)  
• the route of administration  
• and of course, the dose 

Progestogens 

Progestogens are drugs that are similar to progesterone. There are two types of progestogens used for MHT: 

• synthetic versions of progesterone (such as dydrogesterone, medroxyprogesterone, norethistherone, levonorgestrel, norgestrel and drospirenone)
• micronised progesterone, which is chemically identical to the progesterone found in your body but made from plants

Progestogens are usually prescribed together with oestrogens because they counteract the thickening of the womb lining caused by oestrogens. If you have had your womb removed, you may be prescribed oestrogens alone. 

Women vary in how well they get on with the synthetic versions of progesterone, and some studies have shown that micronised progesterone has fewer side effects than synthetic progesterone. It’s important to discuss your needs and the pros and cons of different hormone treatments with your doctor.

Testosterone 

Although testosterone is often referred to as the ‘male’ hormone, it’s also produced naturally by your ovaries. Your testosterone levels decrease as you transition to the menopause, which can sometimes lead to low libido. In some women, testosterone may be prescribed to improve libido or address hypoactive sexual desire disorder (HSDD), especially if oestrogens and progestogens haven’t improved their libido.   

When reading up on HRT, you might come across the term ‘bioidentical hormone’ – this means that the hormone treatment (whether it’s an oestrogen, progestogen or testosterone) is very similar to the equivalent hormone that your body produces naturally. These hormone treatments may come with a lower risk of blood clots and breast cancer risk when compared to non-identical HRT, such as synthetic progestogens.

Body-identical or not?

Body-identical just means hormones (estradiol, progesterone, or testosterone) that are molecularly identical to the estradiol, progesterone, and testosterone made by the body.  

All hormonal medications (body-identical or not) are synthesised in a lab from a plant sterol precursor, so the concept of ‘natural’ or ‘plant-based’ doesn’t come into it. Body-identical hormones (also called bioidentical hormones) are ‘natural’ only in the sense that they’re molecularly identical to the body’s own hormones.   

Testosterone and oestrogen

For testosterone and oestrogen, most modern conventional preparations are body-identical. Exceptions include  ethinylestradiol and ‘conjugated oestrogens’, which is an old-style oestrogen drug that contains about 30 different hormones, including androgens, many of which are not body-identical.  

Progesterone 

For progesterone, it’s a very different story. Until recently, most so-called ‘progesterone’ formulas were actually synthetic progestogens such as:  

• medroxyprogesterone acetate  
• levonorgestrel  
• norethisterone  
• drospirenone  

And unfortunately, progestins have quite different effects on the body compared to progesterone, especially when it comes to breast health. In fact, the latest research suggests that progestins (not oestrogen) were responsible for the breast cancer risk associated with small menopausal hormone therapy.  

In contrast, body-identical progesterone is safer for breasts and according to some experts, may even reduce the risk of breast cancer. Body-identical progesterone is called ‘oral micronised progesterone’ because:  

The progesterone has been micronised or emulsified for better absorption. 

Without such preparation, progesterone cannot be absorbed orally, which is actually why progestins were invented in the first place. 

Tip: To know if the hormones you’re taking are body-identical, read the label.

Conventional vs Compounded Formulations

Conventional hormone therapy refers to hormone formulations (oestrogen and progestogens) that are:   

• commercially available products,  
• and are approved as medicines by a country’s pharmaceutical regulatory authority (the MHRA in the UK).  

Compounded hormone formulations are made by compounding pharmacies according to the prescription issued by the woman’s doctor. The exact mix of oestrogen, progesterone, and testosterone varies depending on the prescription, but formulations are almost always body-identical.  

Compounding pharmacies and the ingredients they use are regulated — but the individualised formulations are not approved medicines according to pharmaceutical regulatory authorities, and are therefore described as ‘unregulated’.   

Confusingly the terms ‘bioidentical’ or ‘BHRT’ (bioidentical hormone replacement therapy) are sometimes used to refer to compounded formulations too, but as we’ve seen, both conventional and compounded formulations can be bioidentical or body-identical!

The use of compounded bioidentical hormone replacement therapy is controversial. Indeed, the British Menopause Society does not recommend their use because of lack of evidence concerning their effectiveness and safety. They also point out that there isn’t good evidence to justify lots of blood and saliva hormone tests that are claimed to tailor therapy to the individual. Lots more studies are required, but for now the jury seems well and truly out on the use of compounded treatments. You should speak to your GP or menopause specialist if you are considering going down this route. 

Oestrogen can be administered through:  

• tablets (oestrogen alone or combined MHT)   
• skin patches (oestrogen alone or combined MHT)  
• gels rubbed into the skin  
• sprays (used on the skin)  
• implants (small, pellet-like implants inserted under the skin)  
• or a vaginal pessary, cream or ring 

All these methods have their pros and cons. For example:  

For some, taking tables may be the easiest way of having HRT treatment, but oral oestrogens can increase the risk of blood clots. That’s especially true for oral conjugated oestrogens.  

Transdermal (through the skin) methods such as patches and gels don’t increase your risk of blood clots but are not always absorbed well.  

Finally, vaginal oestrogen only has an effect within the vagina and so can be very helpful for symptoms like vaginal dryness, but won’t have an effect on other menopause symptoms like hot flushes. Scientists currently believe that vaginal oestrogen does not increase the risk of breast cancer and can be used even for women with a history of breast cancer.   

Progestogens can be administered through: 

• tablets (progestogen alone or combined HRT),  
• skin patches (combined HRT),  
• intrauterine systems (IUS) 

Of the two types of progestogens, micronised progesterone tends to have fewer side effects, as well as a lower risk for both blood clots and breast cancer than synthetic progesterone. 

Testosterone is administered as a gel that’s rubbed onto your skin.   

How often you receive MHT will depend on: 

• what stage of the menopause you’re at
• how you want to take MHT (for example, tablets, gel patches, etc)
• your personal preferences

There are two types of MHT routines: cyclical (or sequential) MHT and continuous combined MHT.

Cyclical MHT

Cyclical MHT is usually recommended if you’re experiencing menopause symptoms and are still having periods. There are two types of cyclical MHT:

1. Monthly MHT – You take oestrogen every day, and progestogen for the last 10–14 days of your menstrual cycle. This is usually recommended if you’re having regular periods.
2. 3-monthly MHT – You take oestrogen every day, and progestogen for 14 days every 3 months. This regimen is usually recommended is you’re having irregular periods. On this regimen, you should have a period every 3 months.

By maintaining regular periods on these regimens, you will know when your periods naturally stop and therefore when you’re likely to enter the last stage of the menopause. 

Continuous combined MHT

Continuous combined MHT is usually recommended if you are postmenopausal; if you haven’t had a period for 1 year then you are considered to be postmenopausal. It involves taking oestrogen and progestogen every day. In some cases, you may only need to take oestrogen.

If you started a cyclical MHT regimen while you were in the perimenopause, your doctor may switch you to a continuous regimen once you are postmenopausal. 

Vaginal oestrogen

If you choose to use vaginal oestrogen, the exact regimen will depend on whether you are using tablets, a cream, a pessary or a ring. Except in the case of vaginal rings, you will usually start taking vaginal oestrogen daily and then reduce the frequency gradually.  

 For any of the hormones (oestrogen, progestogen, and testosterone), the dose is very important. Too little or, more importantly, too much of any hormone can cause side effects that require troubleshooting.  

For example, oestrogen can cause either:  

• symptoms of high oestrogen (e.g. headaches and breast pain, swelling in other parts of the body, feeling sick, leg cramps, indigestion or vaginal bleeding),  
• or paradoxically symptoms of low oestrogen (e.g. hot flushes)  

Like oestrogen, progestogens can also cause breast pain, headaches, swelling in other parts of the body and vaginal bleeding. Depression, mood swings and acne are also associated with progestogens. 

If you are taking more than one hormone, it can be difficult to pick apart which hormone is causing which symptom, and/or if it’s related to the dose of anything you are taking. If side effects persist, speak to your GP or menopause specialist, who may recommend switching to a different way of taking hormones (for example, changing from a tablet to a patch), changing what you are taking, or changing your dose.  

Tip: Talk to your doctor about starting low with the dose so you can titrate up as needed rather than trying to troubleshoot side effects from too much hormone.