Women under 40 represent 5 percent of new breast cancers, yet 7 to 15 percent may be pregnant at diagnosis.

Breast cancer risk increases with age, so those numbers are expected to go up as more women delay pregnancy. Risk rises slightly for those having a first pregnancy after age 30. Improved detection in young women may also lead to increased cases.

At one time, doctors and women thought pregnancy was too dangerous to continue during breast cancer treatment. It was believed a woman had to either terminate the pregnancy to start treatment right away, or delay therapy and risk her own survival until after the baby was born. Births were often medically induced (started early by a doctor) to speed time to treatment, causing complications for premature babies.

Now, research shows good results for women who have surgery or chemotherapy for breast cancer at appropriate times during pregnancy. Studies show that:

• Ending a pregnancy by therapeutic abortion (done for medical reasons) does not improve survival in pregnant women diagnosed with breast cancer
• Breast cancer treatment in pregnant women should follow the same therapy guidelines as for non-pregnant women, with some changes to protect the fetus. These include using older medicines, where we have much more information about their impact during pregnancy
• Infants exposed to chemotherapy during pregnancy show normal development after birth

Many women now continue pregnancies during breast cancer treatment. For care, see oncologists and obstetricians or maternal-fetal specialists experienced in helping pregnant women with breast cancer.      

Your doctors may discuss terminating your pregnancy as one option, especially if you are diagnosed early in the first trimester (three months) of pregnancy, or have recurrent breast cancer that requires treatments not known to be safe in pregnant women.

• What you decide to do is a personal choice, dependent upon your situation
• Talk with an oncology social worker or counselor and others you may want to consult

Before treatment begins, your obstetrician or a maternal-fetal expert should examine the fetus.  

Some therapies carry less risk to the fetus than others:

• Surgery

Discuss the timing of surgery and anesthesia risks for your fetus in advance with your doctors and anesthesiologist.

• Mastectomy, removal of breast, may be used in all trimesters
  • avoids need for radiation in most cases
  • when needed, should be done using a similar time between diagnosis and surgery as a non-pregnant woman
• Lumpectomy, removal of part of breast, is used later in pregnancy, so radiation can happen after delivery  
• Axillary dissection removes lymph nodes to see if they contain cancer. Sentinel lymph node biopsy can be done safely during pregnancy with a radioactive tracer rather than blue dye.

• Chemotherapy

In the first trimester, chemotherapy carries a high risk of harm to or miscarriage of your fetus. But some chemotherapy medicines can be used in second and third trimesters.

• In general, the same medicines and dosing can be used as for non-pregnant women.This may include the combination of doxorubicin (Adriamycin), cyclophosphamide (Cytoxan) and 5-fluorouracil, and others
• Methotrexate should not be used in the first trimester because studies show it causes miscarriage  
• We are learning more about taxanes during pregnancy; studies have shown acceptable outcomes for the fetus. Your doctor may consider using taxanes if delaying your treatment until after delivery would be significantly longer than it would be if you weren’t pregnant, or your doctor feels the wait is too long
•   A 2012 study of infants exposed to chemotherapy showed no effects on their general health, growth or neurocognitive abilities

You should not receive chemotherapy in the three to four weeks before delivery. It’s likely you will get regular ultrasounds during chemotherapy to check the growth of the fetus and the condition of amniotic fluid and placenta.

• Radiation Therapy

You cannot receive radiation therapy during pregnancy, unless it’s possible to expose your fetus to less than 5 to 10 rads. Often, this is not possible in breast cancer.

If you need radiation therapy after a lumpectomy, talk with your doctor about whether delaying radiation until after delivery would be too long a delay. In this case, you could consider mastectomy.

• Hormonal and targeted (biologic) therapy should not be given during pregnancy or breastfeeding. Tamoxifen, a hormonal therapy, is known to cause birth defects. Targeted treatments such as trastuzumab (Herceptin) may cause low amniotic fluid, and infants born with reversible kidney issues. It may be possible to take these treatments once your baby is born. 

If you are pregnant and diagnosed with breast cancer, it may help you to talk with others who are going through a similar experience, or have gone through it.

• Hope for Two...The Pregnant with Cancer Network connects women who are pregnant with cancer to support, hope and to share experiences with others who've had the same cancer during pregnancy.
• Breast Cancer Helpline can match you with a Helpline volunteer who is your age or in a similar circumstance. Call us toll-free today: (888) 753-LBBC (5222).
• Young Survival Coalition Diagnosed during pregnancy discussion board is for women in breast cancer treatment while pregnant.

You also may be interested in:

• Pregnancy & Cancer Registry, a confidential database which gathers information about women who are or were pregnant during cancer treatment. A related database collects information on pregnant women who have a history of cancer. Enroll confidentially at (877) 635-4499.