The menopause is the time when menstruation stops because the ovaries stop producing hormones and releasing eggs for fertilisation. This marks the end of a woman's reproductive years.
Hormone replacement therapy (HRT) pills – Kliofem, a combined HRT treatment, containing both oestradiol and progestogen.

Hormone replacement therapy (HRT) pills – Kliofem, a combined HRT treatment, containing both oestradiol and progestogen.

What is the menopause?

Menopause occurs due to a decrease in the function of the ovaries and usually signifies the end of a woman’s reproductive years. The occurrence of menopause is defined by menstrual periods having stopped for at least one year, which reflects the ovaries no longer releasing an egg each month (ovulation. It is a normal process that leads to a reduction in reproductive hormone levels (e.g. oestrogen, progesterone and androgens). As a result, the frequency of menstrual periods initially become less regular and then eventually stop altogether.

At birth, a girl is born with a fixed number of follicles (fluid-filled sacs which contain an egg) in her ovaries. After puberty, some of these follicles are used up each month culminating in the release of an egg (ovulation). This process uses up some of this finite reserve of follicles in the ovaries until eventually the ovaries run out of follicles, leading to menopause. When a woman no longer has enough follicles, hormones such as oestrogen are no longer produced in sufficient quantities and menstrual periods (menstruation) stop.

On average, it occurs at around 51 years of age in the U.K., however the exact timing can vary between individuals (although it usually occurs between the ages of 45 to 55yrs). About 1-4% of women go through menopause before the age of 40yrs, which is considered to be ‘premature’, and is called ‘premature ovarian insufficiency’ (POI).

What is perimenopause?

During the 4-10 years leading up to menopause, women may start to experience symptoms due to reduced production of hormones from the ovaries, which is termed ‘peri-menopause’ (peri- meaning around). This transition time can last for several years.

During perimenopause, menstrual periods may become less regular, the amount of menstrual bleeding may change and symptoms of menopause (e.g. hot flushes) can commence. Fertility is reduced as women approach menopause, however, women can still become pregnant during this time so contraception should still be used if pregnancy is not desired.

After one year without a period has passed, menopause is said to have occurred, and thereafter women are described as being ‘post-menopausal’ (‘post’- meaning ‘after’).

What causes menopause?

The menopause occurs when the ovaries stop functioning, and no longer have enough follicles to make hormones or release an egg each month. This leads to a reduction in hormone levels (especially oestrogen), which may cause a wide variety of symptoms (discussed in more detail below).

It is not precisely known why the ovaries stop functioning and cause a woman to enter the menopause, as the ovaries seem more susceptible to age related decline than many other organs.

Listen to our Hormones: The Inside Story podcast episode about menopause

Listen to our Hormones: The Inside Story podcast episode about menopause

It is also not known why it varies from woman to woman, but our genes are thought to play a role in deciding the timing of menopause, as well as environmental factors such as smoking and exposure to other toxins, which can cause an earlier menopause.

Surgical removal of the ovaries, for example due to cancer treatment, will cause a more sudden onset of menopause, and other treatments for cancer that can cause damage to the ovaries (e.g. radiotherapy or chemotherapy) may also result in an earlier menopause. Causes that lead to menopause before the age of 40 years are discussed in a separate articles on ‘premature ovarian insufficiency’ (POI).

What are the signs and symptoms of menopause?

Most (~80%) women suffer from some symptoms due to menopause, but these can vary in severity between individuals. The average duration of symptoms is 8yrs, and 10% of women have symptoms for more than 10yrs. Some women have few symptoms whereas others may suffer with very intrusive symptoms.

Symptoms can start in perimenopause, several years before periods stop. A common sign of peri-menopause is a change in menstrual cycle patterns, with the time between periods either lengthening or shortening.

Symptoms of menopause may include hot flushes (termed hot flashes in the US), night sweats, sleep disturbance, fatigue, changes in mood, anxiety, vaginal dryness / discomfort, changes in urination, brain fog and joint aches. Many symptoms are worse early after the menopause, and their severity tends to decrease with time, although some women can experience troublesome symptoms for several years.

Decreased production of oestrogen from the ovaries can cause symptoms such as vaginal dryness, soreness, itching, or loss of muscle tone, which can make sexual intercourse uncomfortable or painful. This, along with sleep or mood changes, can lead to loss of interest in sex, also known as reduced libido. Lack of oestrogen can also affect the support tissues to the bladder such that some women may experience needing to urinate more frequently or have problems with bladder control (incontinence).

How is menopause diagnosed?

Menopause is diagnosed when a woman’s menstrual periods have stopped for 12 consecutive months. Therefore, the diagnosis of menopause is usually only confirmed after it has occurred, although symptoms can commence during the perimenopause. However, the presence of typical symptoms of menopause such as hot flushes and night sweats, in combination with irregular periods, are highly suggestive.

Another aid to diagnosis is to measure the levels of hormones in particular follicle stimulating hormone (FSH) in a blood test. A high FSH level is consistent with menopause, as it indicates that the ovaries are no longer functioning and secreting enough hormones such as oestrogen. Low oestrogen levels are sensed by the hypothalamus and pituitary gland, and lead to an increase in the secretion of gonadotrophins (especially FSH) (i.e. there is loss of the usual negative feedback by oestrogen on FSH secretion, and FSH levels rise to try to increase stimulation of the ovaries).

However, an FSH level can be normal during perimenopause, and measurement of this is not needed to make a diagnosis of menopause in women who are over the age of 45yrs. Measuring FSH can also be inaccurate in women who are taking the combined oral contraceptive pill. However, a blood test, including FSH, can be useful to help identify the cause of menstrual irregularity, or to diagnose ‘premature ovarian insufficiency’ (POI), in women under the age of 40yrs.

How is menopause treated?

Some women choose not to have hormone based-treatments, however others have troublesome symptoms or could benefit in other ways such as improved bone health, and choose to have hormonal treatment. Replacement of hormones that would normally have been produced by the ovaries is called ‘Menopausal Hormone Therapy’ (MHT) (previously commonly referred to as ‘Hormone Replacement Treatment’; HRT). The main hormone that is replaced in MHT is oestrogen, which can be given in various ways including tablets, patches, gels, or sprays.

There are many different hormone replacement options but generally all MHT will contain a form of oestrogen and, if needed, a form of progesterone. If a woman still has her womb (uterus) present (i.e. she has not had this surgically removed which is called hysterectomy), oestrogen can stimulate growth of the lining of the womb, and can predispose to the development of abnormal cells (called endometrial hyperplasia), and a small increase in the risk of endometrial cancer. Therefore, in women with a uterus, MHT should contain progesterone in addition to oestrogen to avoid this risk of endometrial cancer.

MHT can be given in different forms:

  • Oestrogen only - suitable for women who do not have a uterus (womb).
  • Cyclical combined - in which oestrogen is given continuously and progestogens cyclically and induces a monthly menstrual bleed. This is more usually used if MHT is started soon after the menopausal transition but can be continued longer if preferred.
  • Continuous combined - preparations in which oestrogen and a progestogen are given together every day. These formulations should not result in any bleeding, especially if not used sooner after the menopause when some irregular break-through bleeding can occur.

Patches and gels are preferred to tablet forms in women with gut absorption problems, or who have abnormal blood lipid profiles (e.g. raised triglyceride levels), or are at risk of venous thromboembolic disease (i.e. clotting in the deep veins of the leg or in the lungs) such as in women with obesity or those who smoke.

For most women, the benefits of taking short-term MHT to improve quality of life during the perimenopause usually outweigh the risks.

In addition to relief of symptoms, oestrogen is also beneficial for aspects of health that do not necessarily result in symptoms such as bones. Consequently, osteoporosis (colloquially referred to as ‘brittle bones’) is more common in women after the menopause. MHT (which contains oestrogen) can therefore help prevent thinning of the bones in women after menopause. Other adjuncts to treatment of women with osteoporosis include vitamin D and calcium supplements, and for some women with a high risk of fracture, additional treatments such as bisphosphonates can be used to improve bone strength.

Synthetic versus bioidentical HRT

There are synthetic forms of licensed MHT which are not identical to the natural hormones produced by pre-menopausal ovaries, such as Premarin (oestrogens conjugated with sulfate esters), and synthetic types of progesterone e.g. medroxyprogesterone or norethisterone, as well as tibolone (a progestogen with metabolites that have oestrogen-like, and androgen-like properties). ‘Progestogen’ refers to any compound with progesterone-like effects, whereas progestins refers to synthetic forms of progesterone. These older, synthetic MHT preparations may be associated with greater risks, for example of blood clots and breast cancer.

There are also MHT preparations containing bioidentical (body-identical) hormones, which are manufactured to be identical to a woman’s natural hormones. There are several licensed ‘body-identical’ MHT preparations available on the NHS. These are safe and regulated, such as oral or transdermal oestradiol, and micronized progesterone. Some of the newer synthetic progestogens, such as dydrogesterone, when combined with synthetic oestrogen appear as safe as the body identical formulations.

However, there are some private, non-NHS providers of menopause care promoting the use of unlicensed and unregulatedpharmacy compounded’ MHT preparations (sometime marketed as ‘bioidentical’ or ‘natural’), which means that these preparations are manually put together in the pharmacy. They may sound natural but these unregulated pharmacy compounded preparations may not contain safe amounts of hormones and so could increase the risks of blood clots and womb cancer. There are several preparations that contain oestrogen or progesterone in a form that is identical to that made by the body (and can equally be referred to as ‘bioidentical’), however it is important to use only those preparations that have been produced to highest regulatory standards by a licensed pharmaceutical company rather than pharmacy compounded preparations. In short, it is recommended that all women on MHT take only licensed formulations.

Local Symptoms of Oestrogen Deficiency:

Vaginal creams, pessaries, or a vaginal ring that contain oestrogen, may be helpful for local symptoms such as vaginal dryness, as well as local bladder-related symptoms such as incontinence. These local oestrogen preparations do not carry any of the risks of systemically absorbed MHT (e.g. oestrogen in pills, gels or patches), and can be used safely in all women long-term. They can also be used in addition to systemically absorbed MHT if such symptoms have not been relieved.
Oestrogen creams, pessaries and rings can be used to treat vaginal symptoms of menopause, along with or instead of systemic forms of MHT. Vaginal oestrogen is not associated with an increased risk of breast cancer. As well as vaginal oestrogen, vaginal DHEA is now licensed for vaginal symptoms associated with menopause.

Are there any side-effects associated with MHT?

Side-effects of MHT can include breast-tenderness, water-retention, weight-gain, mood-disturbance, nausea, headaches, and irregular vaginal bleeding. These symptoms can vary by the specific type of MHT used and women should consult their doctor if they have concerns about the side-effects of the MHT that they are taking. Changing the type of MHT preparation or adjusting the dose of hormone treatment can reduce unwanted side-effects.

MHT is primarily indicated to treat women suffering from menopause-related symptoms. There is no time limit on the duration of treatment with MHT, but it is important to consider the balance of risks vs benefits of taking MHT for each individual woman, which should be discussed with a medical professional.

Longer-term use has been linked with a small increase in the risk of breast cancer (discussed in more detail below). An increased risk of blood clots in the veins (known as venous thrombosis) and of stroke is associated with the tablet form of oestrogen in MHT, but not with other modes of administration such as patches or gels. An updated review of the latest evidence by The National Institute for Health and Care Excellence (NICE), which is the national body responsible for evaluating evidence and making treatment recommendations, is currently ongoing. In general terms, some risks are reduced if MHT is started at younger age (less than 60 years of age), and sooner after the menopause has occurred (within 10 years after menopause). Additionally, some risks relate to the duration of treatment (see further details on Breast Cancer below) and so it is recommended to have a review with a medical practitioner at 3 months after starting MHT, and then at least once per year thereafter.

Menopause and Breast cancer

Risks in healthy menopausal women

Although the risk of primary breast cancer is low for most women who take MHT, the risk of primary breast cancer diagnosis does increase with combined forms of MHT (i.e. containing both a form of oestrogen and progesterone) over several years. Women with several risk factors for breast cancer should carefully review the balance of risks and benefits with MHT closely over time in discussion with their medical practitioner.
Risk factors for breast cancer include a family history of breast cancer, especially in first degree relatives, excess alcohol intake, sedentary lifestyle, increased bodyweight, smoking, previous radiation exposure to the breast area, dense breasts, and older age.

Risks in women who have had breast cancer

After most types of breast cancer, the risk of recurrence is elevated if a woman takes MHT. There are many safe alternatives to MHT that can be used to help treat menopausal symptoms in women after breast cancer. Lifestyle adjustments can also help. Exercise and staying active can help manage some symptoms of menopause, as well as reducing breast cancer risk, with 30 minutes of walking or other exercise five times per week reported to reduce the risk of breast cancer by up to 55%. If a woman is struggling with symptoms of menopause after breast cancer, her breast cancer team can advise about the best and safest treatment and support.

Non-oestrogen containing treatments

A second-choice alternative to MHT for the treatment of hot flushes, includes non-hormonal medications such as Selective Serotonin Reuptake Inhibitors (SSRI for short), or Serotonin and Norepinephrine Reuptake Inhibitors (SNRI), or clonidine.

Soon, a new class of drugs called ‘neurokinin 3 receptor antagonist’ will be available, which work by blocking the action of a brain chemical called ‘neurokinin B’ or NKB for short, that is responsible for instigating hot flushes. These drugs are very effective for the treatment of hot flushes and have the advantage of not containing oestrogen (nor affecting oestrogen levels), and thus can be used safely in women at increased risk of breast cancer for example (see preceding section on breast cancer risk with MHT for more detail).

There are also non-hormonal lubricants and moisturisers that can help with associated local symptoms such as vaginal dryness.

Non-pharmaceutical treatments such as cognitive behavioural therapy (CBT) can also help with symptoms such as hot flushes or mood disturbance.

There are also several complementary therapy treatments available, such as St John’s wort, however it is harder to guarantee the quality of such products, and some can interfere with other medications, so always discuss these with your medical practitioner.

Testosterone treatment

Aside from oestrogen, the ovaries also normally produce androgens such as testosterone in premenopausal women. Therefore, some women can experience symptoms due to low testosterone levels after the menopause, which may include reduced libido (low sexual desire). While low sex drive can be multi-factorial and psychosexual factors should be considered and addressed, a trial of testosterone can also be considered. This is usually done through a testosterone-containing skin gel or cream. Only one preparation is currently licensed in women (Androfeme) but it is so expensive that it is not widely available through the NHS. Some doctors prescribe skin gel testosterone (which is licensed and widely available for use in men), for use in menopausal women at a lower dose. The main concern is excess testosterone replacement, which can cause side-effects such as acne, increased facial and body hair, mood and voice changes. So, testosterone replacement for menopause related symptoms should only be prescribed by a doctor experienced in prescribing this in women.

Menopause in the workplace

Women of menopausal age represent the fastest growing demographic in the UK workplace today. As such, it is important that they are supported by their healthcare professionals and employers if menopause is affecting their ability to work. A menopause friendly workplace and reasonable adjustments, tailored to individual needs, can help women remain in employment and continue to achieve career progression. Gender balance in the workplace is likely to benefit everyone. There are several national guidelines advising employers about considerations for menopause in the workplace and the government has set up a working group with the aim to improve gender parity and retention of female employees going through menopause.

Listen to our Hormones: The Inside Story podcast episode on menopause

Visit the British Menopause Society for other helpful information.

Last reviewed: Apr 2022