Breast cancer during pregnancy

Breast cancer during pregnancy is rare. Find out how breast cancer is diagnosed and treated if you are pregnant and where you can get help and support.

Finding out you have breast cancer while you are pregnant is very upsetting. You are likely to feel a range of emotions that may include anger, sadness or fear.

Breast cancer during pregnancy is rare. Research shows that breast cancer is reported in 1 in every 3,000 pregnancies. Most women are between 32 and 38 years old at diagnosis. Most are able to carry on with their pregnancy.

Rarely, some women may need to think about whether to end the pregnancy (termination). Your doctor will discuss your options but they may recommend it if you:

  • need chemotherapy
  • are less than 14 weeks pregnant

Even then, it might be possible to delay your chemotherapy treatment until you are more than 14 weeks pregnant. Deciding to end your pregnancy is a very difficult decision and only you can make it.

It can help to discuss your options with your family, breast care nurse, cancer specialist and your obstetrician. There isn't any good research evidence to show that being pregnant makes a cancer grow more quickly.

Diagnosing breast cancer

Your breasts change when you are pregnant, becoming ready for breastfeeding. The breast tissue becomes more dense. Dense breast tissue has less fat and more breast cells and connective tissue. 

This can make it more difficult to find changes in the breasts. See your GP if you feel any lumps. They will examine you and if they have any concerns they will refer you to a breast clinic.

The first test you have is an ultrasound scan. This uses sound waves and is safe for your baby. You might also have an x-ray of your breast (mammogram). To protect your baby they will shield them from the radiation if you need to have one.

To find out if there is cancer you usually have an ultrasound guided biopsy. The doctor uses an ultrasound probe to find the abnormal area and take a tissue sample (biopsy). The biopsy is then sent to the laboratory to be looked at under the microscope.

There are some tests that doctors don’t usually recommend if you’re pregnant, including CT scans and bone scans. This is due to the potential risk to the baby from the radiation. Your team will usually use other types of tests such as an ultrasound, MRI or x-ray to check other parts of the body. 

Treating breast cancer

The aim is to balance treatment for your cancer and keeping your baby safe and well.

You have a team including cancer doctors, obstetricians and midwives looking after you and making a plan for your treatment. Doctors try and keep your treatment as close as possible to what someone who isn’t pregnant would have. This includes not delaying treatment.

The type of treatment you have depends on:

  • your wishes
  • how many weeks pregnant you are (which trimester you are in)
  • your type of breast cancer and if your cancer has spread


Surgery is possible at any time during pregnancy. Having reconstructive surgery to your breast at the same time as having the cancer removed can make the operation much longer. Usually, your team will recommend you have a second operation after you have given birth.


Doctors normally recommend having radiotherapy after you’ve given birth. This is because they don't want the baby exposed to radiation. There are some changes that can be made to help protect your baby if there is no other option than having radiotherapy.


You can’t have chemotherapy if you are in your first trimester of pregnancy. The chemotherapy can harm the baby or cause a miscarriage. Your doctor will want to delay your chemotherapy treatment until you are at least 14 weeks pregnant.

At the moment research shows that after 14 weeks, children exposed to chemotherapy don’t have any more problems than those who aren’t exposed.

Your chemotherapy should stop 3-4 weeks before delivery. 

This is because chemotherapy:

  • increases the risk of infection during delivery
  • increases your risk of bleeding when giving birth

Hormone therapy, immunotherapy and targeted cancer drugs​

Doctors don't recommend hormone treatment, immunotherapy or targeted cancer drugs for breast cancer until after you have given birth. As they could harm the developing baby.

Immunotherapy and targeted treatments are newer treatments. So there isn't much evidence about how they could affect the developing baby.

You usually start hormone treatment after you've had your baby. You can't have hormone treatment while you are breastfeeding.

Talk this through with your specialist team.

Other treatments

There are lots of ways of controlling sickness or pain for women who are pregnant. Research shows that common anti sickness medicines such as ondansetron are safe to take in pregnancy.

Having your baby

Your team will plan for you to have your baby as close to your due date as possible. Depending on your treatment plan and due date your obstetrician might give you medicines to help you have your baby early (induce your birth) so you have a vaginal delivery. Or it may be safer for you to have a caesarean section. This is when you have an operation to remove your baby through your tummy (abdomen). 

Breast cancer has never been known to spread to a baby. The doctors will collect your placenta after birth and look at it down a microscope. It’s very rare, but cancer cells could spread there.

Your cancer doctor and midwife will let you know if you will be able to breastfeed after your baby is born. Some cancer drugs pass into the breast milk.

Practical and emotional support

After you have had your baby you may need to continue treatment. This might make caring for your baby more difficult, especially if you have other children at home.

Ask for help if you need it. It might help to plan ahead and find out what people close to you can do to help.

Your team can also refer you to a counsellor for extra support at this difficult time.

You can also call the Cancer Research UK information nurses on 0808 800 4040 Monday to Friday, 9am to 5pm, to talk about being pregnant, having breast cancer and any concerns you have.
Last reviewed: 
10 Mar 2021
Next review due: 
10 Mar 2024
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  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact with details of the particular issue you are interested in if you need additional references for this information.

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