Breast cancer during pregnancy

If you develop breast cancer during pregnancy the treatment you are offered will depend on the type and extent of your breast cancer, the trimester of your pregnancy when the cancer is diagnosed and your individual circumstances.

Each trimester of pregnancy represents a number of weeks:

  • First trimester – from conception to 12 weeks
  • Second trimester – 13-28 weeks
  • Third trimester – from 28 weeks to delivery

Effective treatment for breast cancer can be given during pregnancy without affecting the baby. You cannot pass cancer on to your baby and there is no evidence that having breast cancer during pregnancy affects your baby’s development in any way. Your treatment team will include an obstetrician (a pregnancy and childbirth doctor) as well as your breast cancer specialist.

Breast cancer is normally diagnosed by triple assessment carried out at a specialist breast clinic.

Continuing your pregnancy

Terminating the pregnancy isn’t usually recommended when breast cancer is diagnosed. Most women will be able to carry on with their pregnancy while having breast cancer treatment. However, some women choose not to. The decision to terminate a pregnancy is a very personal one and you should discuss this with your partner (if you have one), your specialist team and obstetrician.

There’s no evidence to suggest that a termination will improve the outcome for women diagnosed with breast cancer during pregnancy. However, termination may be discussed if chemotherapy is recommended during the first trimester.

Whatever you decide, it’s important to make the right choice for you.

Treatment during pregnancy and after delivery

The following are treatments that you may be given depending on your trimester and whether you have delivered your baby. If you are near to the end of your pregnancy, your specialist may delay your treatment until after the birth. If you are breastfeeding you will be advised to stop before receiving any treatment.


Surgery can safely be done during all trimesters of pregnancy. Many women with breast cancer are given a choice between mastectomy and breast-conserving surgery. A mastectomy is removal of all the breast tissue including the nipple area, while breast-conserving surgery, usually referred to as lumpectomy or wide local excision, is where the cancer is removed along with a margin of normal breast tissue. During pregnancy you’re more likely to be offered a mastectomy. This is because not all women who have a mastectomy need radiotherapy whereas radiotherapy is needed after breast-conserving surgery. Radiotherapy is generally not recommended at any time during pregnancy.

If you are diagnosed in your second trimester and will be having chemotherapy after your surgery, you may also be able to have breast-conserving surgery (if appropriate) instead of a mastectomy. This is because radiotherapy will not usually be given until after your chemotherapy has finished, and after your baby has been born.

Your specialist team will also want to check the lymph nodes under your arm (you may already have had a lymph node biopsy at the time of your diagnosis). If tests before your operation show that your lymph nodes contain cancer cells, an operation to remove all of your lymph nodes (a lymph node clearance) will be recommended. If not, you may be offered a sentinel lymph node biopsy to identify whether the first, or sentinel, lymph node (or nodes) are clear of cancer cells. If the biopsy shows the node (or nodes) are affected, you may be recommended an operation to remove some or all of the remaining lymph nodes.

A sentinel lymph node biopsy uses a small amount of radioactive material (radioisotope) which does not affect the pregnancy. However, the blue dye that is used alongside the radioisotope to identify the sentinel node is generally not recommended during pregnancy. Your surgeon will discuss whether sentinel node biopsy is a suitable option for you.

Whichever type of surgery you have, it will involve having a general anaesthetic. This is generally considered safe during pregnancy, but there may be a slightly increased risk of miscarriage, especially early on in the pregnancy.


Certain combinations of chemotherapy can be given during pregnancy. However, it should be avoided during the first trimester as it may cause harm to the unborn baby or cause miscarriage. Generally, chemotherapy during the second and third trimesters is safe.


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.

Other treatments

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.

Further support

There is a private Facebook group set up by younger women diagnosed with breast cancer called Younger Breast Cancer Network. You can find it on Facebook by searching ‘Younger Breast Cancer Network’. Several members of the group have been diagnosed during pregnancy or soon after given birth.

Mummy’s Star is a charity supporting pregnancy through cancer and beyond.

Last reviewed: March 2015
Next planned review begins 2017

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