Pregnancy and Breast Cancer

Breast cancer is the most common cancer in pregnant and postpartum women, occurring in about 1 in 3,000 pregnancies. The detection of a lump may be hindered by the natural tenderness and engorgement of the breasts of pregnant and lactating women. It is important to know what is normal for your breasts and to be aware of any changes in their look or feel and to have a clinical breast exam as part of routine doctor's visits if you are pregnant or lactating.

Effective treatment, including surgery and chemotherapy, can be administered during certain times of pregnancy. Treatment will be decided based on the stage of fetal development and the stage of cancer. The use of radiation therapy during the first and second trimester of pregnancy is not recommended due to the inability to shield the baby from the radiation. For women in early stages of cancer, treatment usually consists of a mastectomy followed by chemotherapy in the second trimester.Chemotherapy given during the second and third trimesters, under close maternal-fetal monitoring, does not put the fetus at greater risk. Recent research from 2025 shows that pregnant patients with breast cancer treated with chemotherapy during pregnancy had outcomes comparable to or even better than non-pregnant patients, with careful monitoring ensuring both maternal and fetal safety. Low birth weight may sometimes be a concern, so close monitoring throughout pregnancy is essential. Women at more advanced stages of cancer have much more difficult choices laid before them as to whether they should delay treatment until after birth or start a less aggressive form of chemotherapy, which may not be effective to fight their cancer. It is important for women facing these choices to discuss possible implications with physicians and specialists, as well as to get support from their friends, family and partners.

• What are my treatment options for my stage of pregnancy/stage of cancer?
• Is there a risk to my baby because of these treatments?
• Can I delay treatment until after the birth? Why or why not?
• What is the likelihood that my cancer will advance with delayed treatment?
• Can I breastfeed my baby?
• Can you recommend a genetic counselor?

You may also want to visit the following websites for more information:

• NCI Pregnancy and Breast Cancer
• Fertile Hope

There is no evidence that breast cancer will affect a baby's development nor that cancer can be passed on to a baby in the womb. If you are diagnosed during pregnancy, you may want to consider participating in a cancer registry which collects information about the diagnosis and treatment of cancer in pregnant women. Dr. Elyce Cardonick, a Maternal Fetal Medicine physician at Cooper University Hospital, collects information about the diagnosis, and treatment of cancer in pregnant women. This information (kept strictly confidential) will help study the effects of a newly diagnosed cancer and treatment, if any, on a concurrent pregnancy. Following the development and behavior of the children after delivery is a long term goal as well.

Some women can and do become pregnant after breast cancer, and recent studies suggest that pregnancy after breast cancer should not increase your risk of recurrence. However, you should consult your doctor before attempting to get pregnant. It is important to realize that certain cancer treatments can affect one's ability to bear children, and careful thought and planning is necessary to preserve fertility before and during treatment.

There are some clinical issues to consider when thinking about pregnancy after breast cancer:

• Impact of chemotherapy on ovaries – At birth, every woman is born with a full complement of eggs in her ovaries to last a lifetime, expending one each month with her menstrual cycle. However, chemotherapy can damage ovaries in a variety of ways. Even if you didn't experience menopause, chemotherapy may kill some eggs completely, or may have damaged your remaining eggs, so they may be incapable of fertilization or may cause genetic defects. Consult a fertility specialist to determine the quality of your eggs and whether you have a chance at a successful pregnancy.

• While recommendations vary, recent studies suggest that pregnancy after breast cancer does not increase risk of recurrence. Most oncologists now recommend waiting approximately 2 years after completing treatment before attempting pregnancy, though individual circumstances may require longer waiting periods. The previous recommendation to wait five years is now considered outdated for most patients. You should consult your doctor about the appropriate timing based on your specific diagnosis, treatment, and cancer subtype.

• Extended treatment – Some women require additional hormonal therapy after treatment, such as 5-10 years of Tamoxifen, which can further delay pregnancy. Speak with your doctor about the possibility of taking a break from Tamoxifen to have children.

If you have had a mastectomy or lumpectomy with radiation you can still breastfeed from the unaffected breast. In fact, your remaining breast may produce more milk to compensate. If you are diagnosed during or immediately following pregnancy, breastfeeding can be harmful to babies as chemicals from drug treatments can pass through the milk ducts.