Overview

Getting a diagnosis of breast cancer while you’re pregnant isn’t a common occurrence. It’s estimated to happen in about 1 in 1,000 to 1 in 10,000 pregnancies.

Pregnancy-associated breast cancer includes breast cancer diagnosed any time during the pregnancy or in the first year postpartum.

It’s possible that breast cancer in pregnancy has increased because more women are having children later in life. The risk of developing breast cancer rises with a woman’s age.

Being pregnant doesn’t cause breast cancer, but if you already have some breast cancer cells, the hormonal changes of pregnancy may cause them to grow.

Continue reading to learn more about breast cancer during pregnancy, treatment options, and what you can expect for yourself and your baby.

Breast cancer and pregnancy: Treatment that considers the baby’s health

Diagnosing and treating breast cancer are complicated by pregnancy. The goal is to cure the cancer, if possible, or to keep it from spreading while also protecting the health of your baby. Your cancer care team and your obstetrician will need to coordinate to provide the best care for you and your baby.

There are no known cases of breast cancer spreading to a fetus, although there are cases where it has been found in the placenta. In a study that followed children who were exposed to chemotherapy in utero for more than 18 years, none were found to have cancer or other serious abnormalities.

Some treatments may have to be delayed until after the baby is born. The goal is to carry the baby as close to full term as possible.

Chances of survival are unlikely to improve by ending the pregnancy. When compared with women who aren’t pregnant and have similar types of breast cancer, both groups have the same general outlook.

What are the treatment options for breast cancer during pregnancy?

When coming up with a treatment plan, much will depend on extent of the cancer. Your doctors will consider:

  • the number and size of tumors
  • tumor grade, which indicates how quickly the cancer can be expected to grow and spread
  • the specific type of breast cancer
  • how far along you are in your pregnancy
  • your general health
  • personal preferences

Surgery

The first-line treatment for breast cancer is surgery, even if you’re pregnant. This may mean breast-conserving surgery (lumpectomy) or mastectomy with lymph node removal.

Breast surgery for early stage breast cancer is considered safe during pregnancy, although general anesthesia may present some risk to the baby.

Chemotherapy

Chemotherapy generally isn’t given during the first trimester of pregnancy, when the baby’s internal organs are developing. Studies show that it’s safer to use some chemo drugs during the second and third trimesters, but it’s not usually given in the final three weeks of pregnancy.

Use of chemotherapy may depend on the specific type of breast cancer you have and how aggressive it is. In some cases, waiting until after you deliver is an option.

Radiation

High doses of radiation given at any time during pregnancy can increase the risks of harm to the baby. These risks include:

For this reason, radiation therapy is usually delayed until after the baby is born.

Hormone and targeted therapies

Hormone therapies and targeted therapies aren’t considered safe to use during pregnancy. This includes:

  • aromatase inhibitors
  • bevacizumab (Avastin)
  • everolimus (Afinitor)
  • lapatinib (Tykerb)
  • palbociclib (Ibrance)
  • tamoxifen
  • trastuzumab (Herceptin)

Mastectomy during pregnancy

Surgery is a primary treatment for breast cancer, regardless of whether you’re pregnant.

Lumpectomy is given in combination with radiation therapy, but the radiation must wait until after the baby is born. This is an option if you’re close to delivery and radiation won’t be delayed too long.

Otherwise, mastectomy is usually the better option. When you have a mastectomy, the surgeon will also check lymph nodes under your arm to see if the cancer has spread. This sometimes involves the use of radioactive tracers and dye. Depending on how far along you are in your pregnancy, your doctor may recommend against this.

General anesthesia may pose some risk to the baby. Your obstetrician, anesthesiologist, and surgeon will work together to decide on the safest time and method to perform the surgery.

Breastfeeding and cancer treatment

It’s possible to breastfeed after a lumpectomy, but scar tissue and reduced milk volume can make it difficult in that breast. Your other breast isn’t affected.

If you have a single-side mastectomy, you’ll be able to breastfeed from the unaffected breast.

Chemotherapy, hormone treatments, and targeted therapy drugs can be passed to your baby in breast milk.

If you would like to breastfeed, talk to your oncologist and your obstetrician to make sure it’s safe. You might also want to speak with a lactation consultant.

Outlook for breast cancer during pregnancy

Learning you have breast cancer while pregnant can be stressful for you and for your family. Consider seeing a therapist to help work your way through this challenging time. Here are some resources to get started: