The Breast Cancer Care charity is calling for improved communication between breast and fertility clinics.
To facilitate this, the charity has set up a toolkit to help clinics develop a referral pathway for young women when they are diagnosed with breast cancer.
Samia al Qadhi, chief executive of Breast Cancer Care, says: “These worrying findings suggest younger women with breast cancer are being left in the dark.
“They are not getting the chance to talk about preserving their fertility alongside treating the cancer.
“On top of being told you have breast cancer, chemotherapy can shatter young women’s hopes of a family.
“After diagnosis there is a short window of opportunity to try and preserve fertility.
“So we are calling for shared responsibility between healthcare professionals to ensure younger women with breast cancer have the conversation they deserve about fertility preservation options as early as possible.
“While fertility preservation may not be wanted by everyone, it is extremely important for thousands of younger women with breast cancer.”