Radiotherapy is not usually recommended at any stage of pregnancy, as even a very low dose may carry a risk to the baby. It can be given after the birth.
Hormone therapy (like tamoxifen and goserelin) and targeted cancer therapies (for example, trastuzumab, also known as Herceptin) are usually not given during pregnancy or while breastfeeding.
More information on these treatments is included in our Treating breast cancer booklet. You may also find it useful to read our Younger women with breast cancer booklet and our Standards of care for younger women with breast cancer.