Illustration by Emma Günther.
Hormone replacement therapy and perimenopause
Everything you need to know about hormone replacement therapy
Top things to know about hormone replacement therapy:
Hormone Replacement Therapy (HRT) uses synthetic hormones to reduce perimenopause and postmenopause symptoms.
HRT comes in two different forms: estrogen-only and combined estrogen and progestin. Both can be taken as pills, creams, patches, or other forms.
HRT can relieve hot flashes, night sweats, and vaginal dryness. It also protects against bone loss.
Risks include a higher chance of stroke, blood clots, endometrial cancer, and breast cancer.
Introduction to hormone replacement therapy
Navigating perimenopause can be challenging and confusing. People don't talk about perimenopause much because it's still a taboo topic and not well-researched. As well as being under-researched, hormonal changes that cause symptoms like hot flashes, mood changes, and sleep disturbances can disrupt your life (1,2). Hormone replacement therapy (HRT) may help treat these symptoms for some people (3). However, like any medication, HRT has benefits and risks (4).
There is a lot of research and debate about the safety and benefits of HRT. Attitudes towards HRT have changed a lot in the past 20 years (5). HRT was once seen as controversial because early studies linked it to an increased risk of breast cancer. There was also thought to be a link between estrogen-only treatment and an increased risk of stroke (5). However, as shown in the section below, these risks depend on your age and medical history. With levels of estrogen naturally decreasing with age, women and people with ovaries are naturally at a higher risk of heart attacks and strokes (4). Additionally, midlife is the time when many people have high cholesterol levels and high blood pressure and are often less active, making them at high risk for heart disease (4). Most experts now agree that HRT can benefit women who start treatment between the ages of 50 and 59, or within 10 years of menopause (5).
Starting HRT within the first four years of perimenopause can significantly reduce the risk of heart disease and can even extend life expectancy (6). The risks and benefits of HRT depend on when you start and who you are (7). For women aged 60 to 79, HRT did not have the same positive effects as in previous studies (5).
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What is HRT and how does it work?
Hormone Replacement Therapy (HRT) is a treatment in which a person takes synthetic estrogen and/or progestin, the synthetic form of the hormone progesterone. HRT replenishes the naturally declining levels of estrogen and progesterone which occur during perimenopause and menopause (4,8,9). This replenishment can reduce the symptoms of hormonal changes (10) like unpredictable menstrual cycles (2), hot flashes (11), vaginal dryness (2), mood changes (1), and sleep disturbances (2).
Perimenopause, the time leading up to menopause, can last anywhere from a few months up to 11 years. On average, it lasts around four to five years (12-15). Menopause is the point in time at which someone hasn’t had a period for a full year (4).
The two main types of HRT are estrogen-only and combined estrogen and progestin (16). HRT can be administered in different forms, such as pills, patches, gels, or creams (16). Read on to learn more about each type.
What are the different types of HRT?
Estrogen-only HRT
Estrogen is the primary hormone used in HRT (5). As the name implies, estrogen-only HRT treatment contains the hormone estrogen, without progestin. It’s commonly prescribed for people who have had a hysterectomy (17).
Estrogen-only HRT is available in two forms:
Systemic estrogen therapy: A high dose of estrogen is released into the bloodstream and helps to manage various vasomotor symptoms, like hot flashes and night sweats (10). Systemic estrogen therapy can be taken in different forms, such as pills, patches, gels, and sprays (10).
Local estrogen therapy: This is generally prescribed for people experiencing genitourinary symptoms, like vaginal dryness, burning, and pain during sex (18). It’s applied to the vagina through creams, tablets, suppositories, and rings and delivers small doses of estrogen directly to the vaginal tissue (19).
Combined HRT (estrogen and progestin):
Combined HRT includes both estrogen and progestin.
Combined HRT is often prescribed to manage vasomotor and genitourinary symptoms, which happen due to reduced estrogen levels (2,20,21). These genitourinary symptoms include vaginal dryness and urinary incontinence (6,20). Combined HRT can help stabilize hormone levels, reduce the intensity and frequency of hot flashes and night sweats, improve mood, and promote better sleep (6). Often, people who are already prescribed systemic estrogen therapy will also be prescribed combined HRT in order to reduce the risk of endometrial cancer from excess estrogen (10).
Combined HRT dosages depend on a person’s menstrual cycle. For those with ongoing periods, cyclical dosing (using different dosages during specific weeks of the menstrual cycle) is often prescribed (22). For those who have stopped having a period, continuous dosing—without a break—is usually prescribed (23). Continuous dosing is not appropriate for perimenopausal women (23).
What are the benefits of taking HRT?
HRT can reduce symptoms of menopause and perimenopause, improve your quality of life, and promote overall well-being.
These benefits include (1,6,10,24-26):
Reduction of hot flashes, poor sleep, night sweats, and irritability
Relief from vaginal dryness
Protection against bone loss, which helps to reduce the risk of osteoporosis and bone fractures
Decreased risk of death from coronary heart disease in women who are younger than 60. This effect is more pronounced in people who start estrogen-only treatment within 10 years before menopause.
Decreased risk of colon and rectal cancers when treated with combined estrogen and progestin
What are the risks of taking HRT?
HRT, like any medication, comes with certain risks. The risks vary depending on the type of HRT you take.
Both combined HRT and estrogen-only HRT are associated with a small increased risk of breast cancer.
Both combined HRT and estrogen-only HRT are associated with a small increase in the chance of stroke (4). This risk decreases soon after you stop treatment (27).
Both combined HRT and estrogen-only HRT are associated with a slightly higher risk of gallbladder disease (4).
Both combined HRT and estrogen-only HRT are associated with a slight increase in the risk of heart attack (4). This risk can be influenced by age, pre-existing medical conditions, and the timing of HRT initiation (4). Those with heart disease or an increased risk of heart disease may face a higher chance of developing heart issues (26). This risk is particularly noticeable within the first two years of starting HRT (26).
Combined HRT and estrogen-only HRT taken in pill form are associated with a slightly increased risk of developing blood clots (26). This risk decreases with time (26). HRT administered via patch, gel, cream, or spray is associated with a lower risk of developing blood clots (4,18,27).
Estrogen-only HRT is associated with an increased risk of endometrial cancer in people who have not had a hysterectomy (4). On the other hand, combined HRT is associated with a lower risk of endometrial cancer (6,27).
Obesity, smoking, physical inactivity, genetics, advanced age, and a family history of blood clots or breast cancer may increase the risk of blood clots and breast cancer when using HRT (5). Also, if you have a history of breast cancer, endometrial cancer, stroke, heart attack, blood clots, or liver disease, systemic HRT is generally not recommended (10). Lastly, if you’re pregnant or suspect you may be pregnant, stop taking HRT immediately and speak to your healthcare provider (10).
What are the side effects of HRT?
Common side effects of HRT include (10,28):
Breast tenderness
Bloating
Changes in mood
Increases in blood pressure
Uterine bleeding or vaginal spotting
Headache
Change in sexual desire
Upset stomach
Change in menstrual flow
Swelling in hands, feet, or legs
If you’re taking HRT and notice that any of these symptoms are persistent or worsen, speak to your healthcare provider (28). You can switch to Perimenopause mode in Clue, which includes tracking options such as hot flashes, night sweats, and sleep quality. Tracking your experiences with Clue can be a helpful way to understand how HRT affects you and your symptom patterns and to analyze changes over time.
Conclusion
If you're experiencing bothersome perimenopausal symptoms, HRT may help, but it’s not suitable for everyone (3). Speak to your healthcare provider or OBGYN to determine if HRT is the right choice for you. It's a good idea to discuss your experiences, personal history, and family history with your healthcare provider and ask about potential risks and benefits based on your health history.
FAQs
Which HRT is best for perimenopause?
The type of HRT that is best for you will depend on your medical history and your perimenopausal symptoms (3). It’s best to talk with a healthcare provider to decide which treatment is best for you and to learn about the side effects and risks of different types of HRT.
Does hormone replacement therapy increase the risk of breast cancer?
Both combined HRT and estrogen-only HRT are associated with a small increased risk of breast cancer. This becomes higher the longer one uses either treatment (4). If you have a family history of breast cancer, systemic HRT is generally not recommended (10).
When should you start hormone replacement therapy?
Most experts agree that HRT can help women and people with cycles who start it within 10 years of menopause, or between the ages of 50-59 (5). Studies show that starting HRT within four years of perimenopause can lower heart disease risk and extend life expectancy (6). The risks and benefits of HRT can vary depending on the age a person starts and the individual themselves (7). For women aged 60 to 79, starting HRT did not show as significant beneficial effects as in previous studies(5).
