How breast cancer treatment affects the menstrual cycle

The month of October is not only for cold weather, but it is also a month of encouraging Breast Cancer Awareness.

Fighting against breast cancer takes a lot of strength, both physical and mental, and it also affects women’s menstrual cycle.

INTIMINA’s Gynaecologist Expert, Dr Shree Datta, answers questions and advises on breast cancer, chemotherapy, and it’s effects on the body.

Can cancer (breast cancer specifically) affect the menstrual cycle and how?

Interestingly, it’s the other way round – studies suggest that the menstrual cycle can influence your risk of breast cancer – for example, the age at which you have your first period, and the age at menopause affect your risk of breast cancer.

This relates to the number of menstrual cycles you have; in fact, the number of periods you have and age of first pregnancy can also affect your risk of breast cancer.

A long or irregular menstrual cycle means you have fewer periods and can lower the risk of breast cancer in younger women. Early breast cancer may not affect your periods. Still, chemotherapy treatment may affect the regularity of your periods, your flow or in some cases, stop periods.

How does chemotherapy affect women’s bodies and menstrual cycles?

Chemotherapy is a powerful cocktail of drugs designed to kill cancer cells, but which can also affect other cells such as those in your ovaries. It can cause menstrual irregularity, your flow pattern, subfertility or it can stop your periods. This can be temporary or permanent and result in symptoms of menopause.

Periods stop in 20-70% of women with breast cancer, but it depends on the woman’s age. Its effects depend on the medications used, the dose given and the woman’s age. Don’t forget that if you are still having periods during chemotherapy, there is still a chance that you can become pregnant.

Other common side effects of chemotherapy include losing your appetite, nausea, vomiting, diarrhoea, mouth ulcers, hair loss, bruising or bleeding, a higher risk of infection, mood changes and tiredness.

How long does it take for a menstrual cycle to come back to normal after finishing chemotherapy?

This varies on the medication regime used, the dose given, length of treatment and the woman’s age. Some studies suggest that periods are more likely to return in younger women (ie. below 40), but this may not always be the case.

In many cases, periods may come back within a few months or up to a year but again may return sooner in younger women.

How many women experience a change in their cycles during chemotherapy?

In addition to the above, whilst periods stop in 20-70% of women with breast cancer, the rate can be less than 5% in women under the age of 30, up to 50% in women aged 36-40. Some mixtures of chemotherapy have a higher risk of stopping your periods, so it’s worth discussing this in advance with your Oncologist.

Bear in mind that even if your periods return, there is a chance that they will be irregular and this may not accurately reflect your fertility. If you have any concerns, it’s better to consult a Gynaecologist early on.

What to do if you lose your period during chemotherapy?

As well as discussing this with your Oncologist, if you are concerned about your fertility, it’s worth consulting a Gynaecologist and in some cases, considering egg freezing. Monitor your menstrual cycle during chemotherapy and afterwards – remember, not all women stop their periods, you may experience an irregular cycle during this time.

If your periods do stop, you may experience symptoms of menopause, such as hot flushes and night sweats, which in themselves may warrant further treatment.

How to get your body back on track after chemotherapy?

People react to chemotherapy in different ways and the time taken to recover from it varies. On the whole, this is no different from those wishing to improve their health – keep a regular daily routine, with a balanced diet, adequate amounts of sleep and try and limit your exposure to stress.

If you’re not sure that you’re getting all the nutrition you need, consult a dietician and consider taking supplements. Avoid alcohol and smoking and try to exercise regularly. Consider meditating and join a cancer support group to speak to other women who have been treated with chemotherapy.

How to keep a positive mind?

There is no doubt that this is a stressful time, and it’s natural to go through a mix of different emotions, so making sure you have a good support network of friends and family is important to help you through the tough spots. Cancer support groups and counsellors may also be helpful to talk through your concerns, feelings and worries.

Is it possible to get pregnant during chemotherapy?

If you are getting periods during chemotherapy, you may still get pregnant. If you’re considering contraception, barrier contraceptives such as condoms or the diaphragm may be the most suitable option. Another alternative may be the copper coil.

The Royal College of Obstetricians and Gynaecologists generally advise waiting for at least 2 years after breast cancer treatment before getting pregnant, due to the risk of relapse, but rest assured many women do go onto have a successful pregnancy after cancer treatment. 

If you’re unsure of your options, consult your doctor early so that we can answer your questions and alleviate your concerns fully.