Menopause is a part of ageing when your periods stop without medication or pregnancy. This usually happens between the ages of 45 and 55. Menopause can also occur due to certain surgeries, such as the removal of your ovaries. Cancer treatments, such as chemotherapy and radiotherapy, may also affect menopause. Some transgender men and non-binary individuals, born female, can also experience menopause.
The menopausal phase can be broken down into three parts: peri-menopause, menopause and post-menopause. The time from the start of your menopausal symptoms (such as less frequent or irregular periods) until your last period is known as peri-menopause and can last several years.
Menopause is a singular event marked by your last period. Menopause is medically confirmed when you haven’t had a period for 12 months (see diagram below). The time after menopause is commonly known as post-menopause.
Fig. Diagram of the peri-menopause, menopause, and post-menopause.
Your body undergoes multiple changes during the time associated with menopause. These are mainly ovarian and hormonal. Your sex hormone levels decrease, changing the typical pattern of your menstrual periods, which eventually stop altogether as the ovaries no longer release eggs.
Other common symptoms of menopause include hot flushes, brain fog and memory issues, sleep disturbances, body shape changes, reduced breast density, weight gain, bone density loss and vaginal dryness.
Menopause does not cause breast cancer. Yet, your risk of developing breast cancer increases with age. It is most common in people over the age of 50 who have been through menopause (8 out of 10 cases) compared to other age brackets.
As you age, mutations can potentially build up in your cells, including those that may increase your risk of breast cancer. Also, post-menopause, oestrogen is mainly produced by fat tissue, which makes up a bigger proportion of your breast. This means the levels of oestrogen in your breast can be higher, which may increase your risk of breast cancer.
If you reach menopause after the age of 55, you have a higher risk of breast cancer. Your risk is higher if you also started your periods before the age of 12. This may be due to a more prolonged exposure to oestrogen circulating in your body.
Having higher levels of naturally circulating sex hormones (oestrogen, progesterone and testosterone) increases your breast cancer risk. Post-menopausal individuals with higher levels of naturally circulating oestrogen have around twice the risk of breast cancer compared to those with lower levels.
Being overweight or obese after reaching menopause is a significant risk factor for breast cancer, and your risk increases the more weight you gain. A UK study found that post-menopausal women who were obese had a 30% higher risk of breast cancer compared to those of a healthy weight.
Type 2 diabetes increases your risk of breast cancer, particularly post-menopause. However, the reason behind this is not completely understood.
Hormone replacement therapy (HRT) is used to manage the symptoms of menopause by replacing either the sex hormones oestrogen and progesterone or just oestrogen. It has been associated with an increased risk of breast cancer. However, your risk depends on the type of HRT you take and the duration of use.
With oestrogen-only HRT, there is little to no increased risk of breast cancer. This type of HRT is usually only recommended to people who have had their uterus removed (hysterectomy).
Combined HRT, which consists of taking a combination of both oestrogen and progestogen, may increase your breast cancer risk when used over five years. Your risk reduces after you stop taking the combined HRT treatment. But some risk remains if used for over ten years.
The decision to take HRT is your individual choice, made in consultation with your qualified healthcare professional based on personal symptoms.
For more details and references, please see our HRT, Menopause and Breast Cancer science review.
Footnote: BCUK aims to use inclusive language where possible. However, when the data is taken from a gender-specific subset, for example women, we respect the gender-specific categorisation used in the data set.
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