Hormone replacement therapy (HRT) relieves symptoms of the menopause by replacing hormones that are at a lower level leading up to and during the start of the process.
Women usually start to experience the menopause between the ages of 45 and 55. During the menopause, the ovaries stop releasing eggs, and levels of the hormones oestrogen, progesterone and testosterone drop, which often causes symptoms such as hot flushes, night sweats, vaginal dryness, reduced libido, disturbed sleep, poor concentration, mood swings, anxiety and brain fog.
During the perimenopause – the period leading up to menopause – a woman can suffer from these symptoms, but still have her period.
For many, the effects of perimenopause and menopause can be challenging, but for others they can be debilitating. HRT can help alleviate symptoms, but some patients are nervous about taking it, in part due to bad press following a couple of studies from more than two decades ago.
How previous studies have shaped our understanding of HRT
In 2002, a study published in the Journal Of The American Medical Association claimed that taking HRT increased the risk of stroke, breast cancer and coronary heart disease. The next year, another study claimed HRT had caused 20,000 more cases of breast cancer over 10 years.
Since then, doubt has been cast on both studies’ methods, while subsequent research has shown that lifestyle factors, such as diet and alcohol consumption, carry a greater risk for breast cancer.
“Obesity, alcohol intake of more than two units a day, or a late menopause all carry a greater risk for breast cancer than HRT itself,” says Dr Edward Coats, consultant gynaecologist and reproductive medicine specialist.
“We are still recovering from the 2002 study, which had a huge dataset, but was flawed. A generation of women have avoided HRT due to worries over increased risks. Menopause experts are looking at how to regain patient trust and communicate the risks and benefits.”
Indeed, for many women, the benefits of taking HRT outweigh any potential risk. Aside from easing menopause symptoms, HRT increases bone density, preventing hip and spine fractures. Even when the dose is low, these benefits remain for many years after stopping HRT.
What are the risks of HRT?
In women aged between 50 and 59, HRT reduces the risk of cardiovascular-related deaths, and does not increase the risk of heart disease or stroke. There is also good evidence that HRT reduces the incidence of bowel cancer.
However, there are a few conditions – endometrial cancer, breast cancer and venous thromboembolism (VTE) – where HRT may do more harm than good. It depends on the patient, so it is important to get specialist advice about the risk factors for these conditions.
VTE is when blood clots form in veins. Taking HRT as a tablet (known as ‘oral HRT’) appears to be associated with at least a doubling of risk of VTE, and the risks increase with age. However, administering the treatment through the skin (known as ‘transdermal HRT’) avoids stimulating clotting factors and can potentially be used by women with a thrombophilic risk – but it needs to be used with extreme caution.
For endometrial cancer, research shows there is no significant risk of malignancy for patients using continuous combined HRT – taking oestrogen and progestogen every day without a break.
In the case of breast cancer, things are slightly more complicated and the risk can depend on the type of HRT being offered and whether or not the woman in question has a uterus. Breast cancer risk associated with taking HRT diminishes when you stop and is no longer evident after five years. And the risks may be lower in women using HRT with body identical progesterone.
However, if patients have previously been diagnosed with breast cancer, it is important that their decision on whether to use HRT is made in conjunction with their oncologist and HRT specialist. More research is needed to give a verdict on whether HRT should be taken if there is a history of breast cancer in the family.
Ninety per cent of breast cancer is sporadic – not genetic or inherited – and so most people are not at an increased risk. When advising patients on whether to use HRT, experts usually weigh up the benefits against the number of relatives affected by breast cancer.
“Deciding whether to use HRT is about understanding risk – and this is where it differs for different people,” says Coats. “For the average person, there are more benefits than there are risks.”
What is the future of HRTs?
In October, the All Party Parliamentary Group on Menopause, which is made up of MPs, called on the government to support women going through the menopause. The group asked for all women to be invited for a menopause check-up when they turn 45, for updated menopause training to be provided for GPs and other healthcare professionals, and for the removal of prescription costs for HRT in England (in line with Scotland, Wales and Northern Ireland).
“A health check for women aged between 45 and 50 would be very useful,” says Coats. “The problem is funding, as currently there are limited resources and rationing of healthcare. However, it is really important that women have access to information about the menopause and treatment options available to them.”
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