A survey for Breast Cancer Care found three-quarters of younger women with breast cancer were not referred to a fertility clinic to discuss their options, while 35% received no information about treatment affecting their fertility.
Every year, around 5,000 women under the age of 45 are diagnosed with breast cancer.
Treatment can affect fertility, with the risks highest for those having both chemotherapy and radiotherapy.
Chemotherapy alone can bring about an early menopause and affect how the ovaries work, but steps can be taken to help preserve fertility. These include freezing eggs or embryos before treatment starts, examining cancer treatments that have the least impact on fertility, and trying to preserve ovarian tissue for use in the future.