There’s been a lot of talk about periods in the Breast Cancer Care office of late. One of our London Marathon runners, Kiran Gandhi, chose to run the race without any sanitary protection to highlight that menstruation can still be a taboo subject.younger woman

However, while this story was gathering headline and opinion pieces, we were contacted by someone who was concerned about her periods being erratic during chemotherapy treatment. It can often be a surprise to people outside the breast cancer world that a cancer in the breast can cause so many side effects beyond it, due to the nature of treatment.

Changes caused by chemotherapy

Chemotherapy causes changes to the ovaries which may lead to changes to periods. Although chemotherapy destroys cancer cells it can also affect any cells that grow and divide rapidly – this includes cells in the ovaries. In turn this can affect the functioning of the ovaries, reducing the number and quality of eggs.

What happens to a woman’s periods during chemotherapy depends on the type of drugs used, the dose given and the age of the woman having treatment. Some women continue to have periods throughout treatment but it’s common for periods to stop during chemotherapy and this can be temporary or permanent. They may restart again at the end of treatment or even months or years later – again this can depend on age. The younger someone is (usually under 35) the more likely it is their periods will return. You can read about other women’s experiences by visiting our Forum.

Many younger women with breast cancer believe the return of their periods means they may be able to have children if they want to. However, this isn’t necessarily the case. The reverse is also true, just because periods are absent or stop/start doesn’t mean you can’t get pregnant, so contraception will be important unless you’re planning for a baby.

Changes caused by hormone therapy

The hormone oestrogen can play a part in stimulating some breast cancers to grow and hormone therapy is used to block the effect of oestrogen on cancer cells. Hormone therapy also effects periods and can make them lighter, irregular or stop all together. Once hormone therapy is completed periods should return, unless the natural menopause has begun during hormone treatment. Again this will be dependent on someone’s age.

The hormone drug, goserelin, may be able to protect the ovaries during chemotherapy by temporarily ‘switching them off’ and stopping periods temporarily. Most women will start their periods again within three months to a year of having their last goserelin injection. 

A time of uncertainty

It’s difficult to say whether someone’s periods will return after breast cancer treatment and this can be upsetting and unsettling for those affected. Not being able to have a definitive answer means those women who want to have children, or who are undecided, may only have the option to wait and see.

At Breast Cancer Care we believe every younger woman diagnosed with breast cancer should be offered a referral to a fertility specialist to discuss fertility preservation options before starting cancer treatment. We have recently developed a toolkit for breast healthcare professionals to encourage open and honest discussions with women about their fertility. Breast Cancer Care is campaigning to ensure all younger women with breast cancer are offered funding for fertility treatment, as the provision of this is currently patchy. 


Get involved with our campaign


Other side effects

Regardless of whether someone wants children, being thrown into an early menopause can be hard to deal with. Alongside menopausal symptoms like hot flushes and vaginal dryness, the reduction in oestrogen can cause osteoporosis. If you are a young woman with breast cancer, aged 45 or younger, you can join one of our Younger Women Together events where you can share your experiences with other women like you.

If you have any concerns about breast cancer treatment or side effects you can talk to our support line on 0808 800 6000. Or you may want to talk to someone who has been there through our Someone Like Me service.