Radiotherapy and pregnancy

Radiotherapy uses high-energy rays to destroy cancer cells. It is not usually given during pregnancy as it may harm the developing baby.

About pregnancy and radiotherapy

Radiotherapy uses high-energy rays to destroy cancer cells. It is not usually given during pregnancy as even a low dose may harm the developing baby.

If radiotherapy is urgent, it may be given to a part of the body that is not close to the womb. For example, if a tumour in the brain is causing increased pressure. But usually radiotherapy happens after the birth.

Breast cancer radiotherapy and pregnancy

Radiotherapy is usually recommended after an operation to remove the area of the breast affected by cancer. This is called breast conserving surgery.

The delay between surgery and radiotherapy is usually 6 to 8 weeks. If you are diagnosed later in pregnancy, you may be able to delay radiotherapy until after the baby is born.

Many young women with breast cancer also need chemotherapy, which they have before radiotherapy. It can take several months to finish the course of chemotherapy. This usually means you will have had your baby before you start radiotherapy.

If you are early in your pregnancy and do not need chemotherapy after surgery, it could mean you have to wait more than 6 months before you have radiotherapy. This delay could increase the risk of the cancer coming back in the breast. Your surgeon may advise you to have the whole of the breast removed (mastectomy).

After a mastectomy, some women need radiotherapy to the chest.

Cervical cancer radiotherapy and pregnancy

Radiotherapy is never given to the pelvic area during pregnancy.

Radiotherapy and chemotherapy is called chemoradiation. This is the main treatment for women with a large area of cervical cancer. It is also used if the cancer has spread into surrounding tissue.

Your doctor may advise you that chemoradiation is the best treatment for you. If your pregnancy is early, they may recommend you think about ending the pregnancy.

You must wait until you are 14 weeks pregnant to have chemotherapy, and until after the birth to have radiotherapy. This wait to have treatment may be a serious risk to your health.

If you decide to continue with the pregnancy, you can start chemotherapy when you reach 14 weeks. If you are later in your pregnancy, you will start chemotherapy straight away.

You have radiotherapy after the baby is born.