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The Menopause Exchange Blog

SIDE EFFECTS OF HRT

The menopause is technically your very last period and is usually caused by running out of eggs. This results in a dramatic reduction in the levels of oestrogen circulating round your body. Not only can this cause menopausal symptoms, but it can trigger a wide range of other symptoms as well. Which ones affect you, and how much, will vary, as the menopause is an individual experience.

This article was included in issue 76 (spring 2018) of The Menopause Exchange newsletter.

Oestrogen replacement
HRT replaces missing oestrogen, which means any symptoms caused by a lack of oestrogen should largely or completely resolve with HRT. However, oestrogen acts on many different parts of the body, so HRT can also trigger normal, but unwanted, effects. Some women find HRT causes breast tenderness due to breast stimulation, nausea due to action on their gut (most likely from tablets) or bleeding due to activity in their uterus. For women who have had a hysterectomy (surgery to remove their uterus), bleeding isn’t going to occur, so they can be prescribed oestrogen on its own.

Progesterone replacement
Progesterone is normally produced by a woman’s ovaries after an egg is released. It prepares her body for pregnancy, causing changes in her uterus that allow the implantation of the fertilised egg. If this doesn’t happen, her progesterone levels drop, and her uterine lining is shed.

If you still have your uterine lining (including if you have severe endometriosis after a hysterectomy), you will need either a synthetic progestogen (progestin) or natural progesterone added to the oestrogen of your HRT. This isn’t just to control bleeding but also to prevent oestrogen-driven stimulation of your uterus, which can lead to precancerous changes.

Once you have had no natural periods for a year, you can use progestin continuously. While this won’t produce period-like bleeds, no bleeding at all can’t be guaranteed and persistent bleeding should be investigated. Otherwise, progestin is used cyclically to produce a predictable period-like bleed or with a progestogen-loaded intrauterine device (Mirena), which greatly reduces bleeding and offers the highest level of protection.

Other body tissues also respond to progesterone, so adding progestin to HRT may trigger side effects. You may experience breast changes (fullness and tenderness), gut effects (nausea and/or constipation) and mood effects.

Micronised natural progesterone produces a side effect profile similar to that of your own hormones. If you use an HRT combination, you will generally have lower blood levels of progesterone and, because your oestrogen levels aren’t lower at the same time, the premenstrual effect is less noticeable. You may notice that your benefit from oestrogen is reduced in the second phase of your HRT cycle. This can generally be managed with a small rise in your oestrogen dose.

Synthetic progestogens are more complex. As well as progesterone-like actions, they either stimulate or block other hormone receptors. This will make the most difference to how they affect your mood (through actions on your brain). They may be more powerful in managing troublesome bleeding. If there’s a significant change in your mood in the second half of a monthly bleed combination, your type of progestin should be changed.

HRT forms
Oestrogen can be replaced in your body using tablets, patches and gels. Implants are only available in some specialist clinics and are generally only used when other methods have failed. This is rare and most likely in young women with a very fast metabolism who have had an abrupt menopause due to surgery.

Oral oestrogen passes through your liver before entering your circulation; in so doing, a significant proportion is broken down (metabolised). In women with very aggressive metabolism or taking medicines that affect their metabolism, standard oral doses may be less effective. Liver metabolism also increases the risks of blood clotting issues, such as deep vein thrombosis (DVT). In women who are fit and well, slim, don’t smoke and have normal blood pressure, the absolute increase in risk is very small and outweighed by benefits. In women already at higher risk, it’s generally not a good idea to increase their clotting risks any further. For them, patches or gels would be a safer choice.

Progesterone isn’t absorbed through the skin but also isn’t affected by the same liver metabolism considerations as oestrogen. The only significant issue affecting women who take progesterone as tablets is that some may have their gut affected (causing nausea or constipation). For them, combined patches (using synthetic progestogen), a Mirena coil or using progesterone vaginally (which isn’t licensed) are the options available.

Occasionally, women may find that a monthly bleed HRT combination triggers cyclical migraine, similar to the effects of their periods. For them, stable hormone levels are vital to avoid changes that may trigger migraine. A typical solution is to use patches with a Mirena coil.

Bleeding issues
If women are in early menopause and are still having regular or reasonably regular periods, they may find their own bleeding is out of time with the HRT pack. The simplest option is to realign at the start of their next period.

Experienced healthcare professionals may suggest changing the HRT. If women feel the combination of their own progesterone and HRT is excessive, they may consider (if their health profile allows) a combined contraceptive pill. This provides both components of HRT but will block egg release and the additional progesterone that follows, as well as acting as contraception.

Getting it right
HRT isn’t a ‘one size fits all’ offering. There are now enough HRT components and combinations that will enable doctors to provide a regimen tailored to the needs and tolerance of every individual woman.  If your own GP or practice nurse can’t get your HRT package right for you, consider seeking more expert help.

Created Spring 2018

Copyright © The Menopause Exchange 2018

About the author
Dr Sarah Gray is a GP in Cornwall who has run menopause clinics for over 30 years and teaches healthcare professionals nationally.

 

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