Most women treated for breast cancer during pregnancy or those who become pregnant after treatment have healthy pregnancies and healthy babies, experts have said.
Breast cancer is rare in younger women, but increasing numbers of young women who have been treated for breast cancer are now going on to have babies, according to Britain's Royal College of Obstetricians and Gynaecologists (RCOG).
Treatment success rates in the UK are good and are continually improving, with five-year survival rates currently around 80pc for the under-50s age group.
New patient information published by the RCOG outlines details for women who are pregnant and have been diagnosed with breast cancer or who have recovered and are planning a family.
For women diagnosed with breast cancer while pregnant, treatment will usually begin straight away and will be offered according to the type and extent of the cancer.
Chemotherapy is not given during the first 13 weeks of pregnancy as it may cause abnormalities in the baby.
After that, it is safe to be offered.
Radiotherapy is not usually offered as a treatment option until after the birth.
Two commonly used drugs - tamoxifen and herceptin - are often given after the initial treatment to reduce the chance of the cancer recurring.