Pregnancy and breast cancer

Breast cancer is the most common cancer in women. Although it is more common in older women, 1 in 11 cases are found in women aged under 45. Treatment success rates are good in the UK and are improving all the time. Increasing numbers of young women who have been treated for breast cancer are now going on to have babies.

On rare occasions, breast cancer is diagnosed during pregnancy, but being pregnant does not seem to affect how successful treatment is.

There are natural changes in your breast when you are pregnant or breast-feeding. However, if you notice a lump it is important you should see your GP or obstetrician who will refer you to the specialist breast team if needed.

You will be offered an ultrasound scan of your breast. Ultrasound is safe in pregnancy.

A small sample (biopsy) of your lump will usually be taken. You will be given a local anaesthetic so you will feel no pain. Your healthcare team will be able to tell from the results if cancer is present. It is important to remember that most breast lumps are non-cancerous.

The treatment you will be offered will depend on the type and stage of your breast cancer, the stage of your pregnancy and your individual circumstances. You will be able to talk about the different treatments available to you with your breast team. You will be given a key worker, often the breast specialist nurse, who will co-ordinate your care and keep in touch with you.

The three treatment options available to you are:

• surgery
• drug treatment
• radiotherapy

Your breast team will discuss with you the best treatment in your situation.

Surgery

Surgery can be carried out at any stage in pregnancy. There are two forms:

• The most common is removal of the lump (lumpectomy). Some of the lymph nodes in the armpit may also be removed.
• Removal of the breast (mastectomy).

Your breast team will discuss both options with you, so that you can make the best decision, together.

Reconstructive operations after mastectomy will usually be delayed until after your baby is born. This is to give time for the hormonal changes in your breasts to settle down after pregnancy.

Drug treatment

Chemotherapy is not given during the first 13 weeks of pregnancy because it might cause abnormalities in your baby.  After that you may be offered chemotherapy depending on your type of breast cancer. Chemotherapy may affect the growth of your baby, and you will be offered extra scans to check your baby’s growth. The anti-sickness and steroid treatments that you may need to control the side effects are safe for pregnant women to take and will not harm your baby.  

For more information, see RCOG Patient information: Having a small baby.

Two commonly used drugs, tamoxifen and trastuzumab (Herceptin), are often given after the initial treatment to reduce the chance of the cancer recurring. However, it is not recommended to take these drugs in pregnancy and treatment will be delayed until after your baby is born.

Radiotherapy

If needed, radiotherapy is usually delayed until after your baby is born.

Most women choose to continue their pregnancy while they receive their treatment for breast cancer. The outcome for breast cancer diagnosed during pregnancy is generally the same whether or not you continue with the pregnancy, or end the pregnancy.

However, if the cancer is advanced when it’s found or is diagnosed in the first three months of pregnancy, your healthcare team will discuss the option of ending the pregnancy (which may involve early delivery of your baby if at a viable gestation) to allow your treatment to start earlier.

This is a difficult decision to make and you will be given the support to make the best choice for you and your family.

A specialist team including a consultant obstetrician, midwife and the breast team, will look after you throughout your pregnancy. Your GP will be kept informed.

Most women who have been treated for breast cancer during pregnancy will carry their babies to full term and can expect birth without complications. If your baby is likely to be born early you may be offered a course of corticosteroid injections, usually over a 24-48 hour period, to help with your baby’s development and reduce the chance of breathing problems caused by being born early.

You can find out more about this from the RCOG Patient Information: Corticosteroids in pregnancy to reduce complications from being born prematurely.

If you are having chemotherapy, the treatment will normally stop 2-3 weeks before a planned birth of your baby to allow your body to recover.

If you have had surgery or radiotherapy you may not produce milk in that breast but the other breast will not be affected. If you wish to breast feed, the midwives will encourage and support you. Breast feeding will not increase the risk of your cancer coming back.

It is perfectly safe to breast feed if you have had chemotherapy in the past. However you should not breast feed if you are still receiving chemotherapy, tamoxifen or trastusamab. It may be possible to breast feed after completion of these treatments, if your milk production can be maintained.

It is important to use reliable contraception during breast cancer treatment. You should not use hormonal contraception such as the Pill or contraceptive implants. Consider non-hormonal contraceptives like the copper coil (intrauterine contraceptive devices) instead. Talk to your breast team about the best contraception for you.

Your plans for future pregnancies should be taken into account when your healthcare team discuss the best treatment with you. Some treatments can affect your chance of a future pregnancy. As with all women, future fertility will also depend on your age.

You should be offered the chance to see a fertility specialist. It may be possible to freeze your eggs or embryos before your treatment begins. Wherever possible, your breast cancer specialist will choose chemotherapy drugs that are less likely to affect fertility.

Other drugs (e.g. tamoxifen and trastuzamab) do not appear to affect fertility, but you should avoid becoming pregnant while taking them. If you are considering a pregnancy while still taking medication, speak to your breast team for advice. Don’t stop any treatment without first discussing it with the team looking after you.

Speak to your breast team before becoming pregnant. You will usually be advised to wait for two years after your treatment has finished before trying for a baby. This is because breast cancer is most likely to come back within 2 years, and further treatment could be more difficult if you were pregnant. Talk to your breast team if you think you may want to be pregnant sooner.

If you have received chemotherapy drugs called anthracyclines before you were pregnant, you should be offered a detailed scan of your heart (echocardiography). This is because there is a small risk of you developing heart problems during pregnancy with these drugs.

The rate of miscarriage, stillbirth and your baby having a birth defect appears to be the same as for anyone else. Pregnancy will not increase the chances of the cancer coming back.