Many women who have not yet had their menopause (change of life) find that their periods are reduced, become irregular or stop completely when they are on chemotherapy. This is because the chemotherapy often affects the ovaries, lowering the normal levels of female hormones. Often these changes lead to the menopause and periods stop permanently.

Age has a strong influence on whether or not periods stop during chemotherapy. At 30 years old only 1 in 10, to 1 in 20 women will be affected, and at 35 years old the odds are only slightly greater. However by 40 it is likely that about 4 out of 10 women treated with chemotherapy will become menopausal and by 45 the figure rises to around 4 out of 5 women. At your age the chance of the menopause is about 50/50.

Once a woman is over 40, if her periods stop it is unusual for them to start again and for about 9 out of 10 women over 40 menopausal changes will be permanent.

If periods return, this usually happens within 3 to 6 months of stopping chemotherapy. If, 3 months or so after the end of treatment, your periods have not come back, your doctors can arrange blood tests which look at the levels of female hormones. These can often give a clearer picture of whether or not the periods will return.