Breast Cancer and Pregnancy

Medically Reviewed by Poonam Sachdev on April 21, 2022
3 min read

It doesn’t happen often, but sometimes mothers-to-be have breast cancer. Getting pregnant doesn't cause the cancer, although the changes in hormones from the pregnancy can make the disease grow faster.

Your breasts thicken while you're expecting, and that can make it hard to spot small masses or lumps. Because of this, breast cancer tumors are often larger and more advanced by the time they’re noticed.

This makes it extra important to have breast exams throughout pregnancy. Any lumps or suspicious symptoms need to be checked by a doctor.

The best thing you can do while pregnant is to see your doctor regularly. These visits are called prenatal (or "before birth") checkups, and they're crucial for keeping you and your baby in the best possible health. During some of these visits, you may have breast exams to check for changes.


A mammogram is considered fairly safe during pregnancy, but it may not be as helpful because of the increased density of the breasts. A three-dimensional mammogram may be a better option.


If a suspicious lump is found, your doctor should do a biopsy. They'll remove a small sample of the suspicious tissue with a needle or by making a small cut. The sample tissue gets checked under a microscope and with other methods to look for any cancer cells.


Your doctor might also give you an ultrasound to assess the extent of any disease and to guide the biopsy.

Ending a pregnancy won’t improve a woman's chances of beating breast cancer. Also, there's no evidence that the cancer harms the baby. But the treatments have risks.

Surgery, in general, is safe during any trimester of pregnancy. If the cancer is still in its early stages, your doctor will most likely recommend removing either the suspicious lump (lumpectomy) or the entire breast (mastectomy). If you're in the first or second trimester, a mastectomy is the preferred surgery. Lumpectomy is usually an option for women diagnosed in the third trimester. Radiation therapy usually doesn’t start until after pregnancy because it can harm the baby.

During breast cancer surgery, the surgeon will examine the lymph nodes to see whether any are affected. They'll often remove the ones where the cancer is most likely to have spread. If you need chemotherapy, your doctor will usually wait until after the first trimester to lessen the chance that it will harm the baby.

Advanced breast cancer usually requires both surgery and chemotherapy, so the risk for the baby is higher. The decision of whether or not to undergo treatment can be a very hard one. Talk with your family and doctor about what's right for you.

There’s no evidence that stopping your flow of breast milk will improve your cancer.

It’s often okay to breastfeed when you have this disease, but talk with your doctor or a lactation counselor to see what's best for you and your baby. If you're getting chemotherapy, you likely shouldn’t breastfeed. Many powerful chemo drugs can travel through your milk to the baby.