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Home > Understanding Breast Cancer > Treatment > Treatment During Pregnancy


Treatment During Pregnancy



Young Women and Breast Cancer
Fact Sheet


Breast Cancer in Pregnancy
Fact Sheet

About 1.5 percent of women with breast cancer are pregnant when diagnosed (about 1 in 3,000 pregnancies) [143].  

There are special treatment concerns for pregnant women who have breast cancer. Although cancer itself does not seem to affect the fetus, certain treatments for breast cancer can be harmful [100].

Diagnosis of breast cancer in pregnant women

Breast cancers in pregnant women may be diagnosed at a more advanced stage than in non-pregnant women [143]. Breast cancer can be hard to detect in pregnant women, leading to delays in diagnosis. Younger women (under age 40) usually do not get screening mammography and screening mammography is not used in pregnant women. Although pregnant women get clinical breast exams as part of prenatal care, the increased size and change in texture of the breasts during pregnancy can make smaller cancers harder to feel.  

Most cancers in pregnant women are found during a clinical breast exam.  

When a suspicious lump is found during the first trimester, tests such as ultrasound (rather than mammography) are used to check the lump for cancer. After the first trimester, a pregnant woman may have a diagnostic mammogram with a shield covering her abdomen to protect the fetus.  

Breast cancer treatment for pregnant women

Surgery and radiation therapy

Mastectomy is usually recommended for pregnant women who are in their first trimester and want to continue their pregnancy [100]. Some women in their second or third trimester may consider lumpectomy (also called breast conserving surgery) [100]. However, radiation therapy is needed with lumpectomy and radiation can harm the fetus. So, women who have a lumpectomy wait and have radiation therapy after the baby is born. This delay does not worsen the prognosis [100]. Some women in their second or third trimester may also have chemotherapy before surgery (neoadjuvant chemotherapy) [100].  

Breast cancer surgery is safe during pregnancy. Although the anesthesia used during surgery can cross the placenta to the fetus, it does not appear to cause birth defects or serious pregnancy complications [144]. Breast reconstruction, however, should be delayed until after the baby is born to avoid further anesthesia and the chance of blood loss.  

Learn more about surgery.

Learn about breast reconstruction.

Learn more about radiation therapy  

Chemotherapy, hormone therapy and targeted therapy

Chemotherapy is not usually given during the first trimester, as this is the time when the chances for drug-related birth defects and miscarriage are greatest [143-144]. During the second and third trimesters, some chemotherapy drugs can be used safely [100,145]. However, chemotherapy should not be given after week 35 of pregnancy or within three weeks of the due date (or planned delivery date) [100]. Many women diagnosed in their third trimester often wait and have chemotherapy after giving birth.  

Hormone therapies (tamoxifen and aromatase inhibitors) and trastuzumab (Herceptin) are not used at any point during pregnancy because of risk to the fetus [100,144].   

Learn more about chemotherapy.

Learn more about hormone therapy.

Learn more about trastuzumab.  


For more information on treatment during pregnancy, visit the National Comprehensive Cancer Network (NCCN) or the American Society for Clinical Oncology (ASCO).  

Prognosis for pregnant women with breast cancer

Prognosis for women with breast cancer is similar to that of non-pregnant women, when age and cancer stage are taken into account (more on cancer stage). Ending a pregnancy does not improve prognosis [143].  

Breastfeeding after a breast cancer diagnosis

If you are diagnosed with breast cancer during your pregnancy and wish to breastfeed after your child is born, talk to your health care provider. Breastfeeding should be avoided while being treated with radiation therapy, chemotherapy, hormone therapy or targeted therapy.

Updated 03/28/14

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