Pregnancy is often a time filled with anticipation and joy. However, for some women, it may also bring unexpected health challenges. While being diagnosed with breast cancer during pregnancy is rare, it is possible, occurring in about one in 3,000 pregnancies, per the National Cancer Institute (NCI). And when it happens, it can be a scary and overwhelming experience. Thankfully, many treatments for breast cancer are safe for both women and their growing baby during pregnancy.
“Being diagnosed with breast cancer while pregnant is a relatively rare occurrence, but it is something that is increasing in frequency as women in general are becoming pregnant a little later in life than they did many years ago,” explains Erica L. Mayer, M.D., a breast oncologist at Dana-Farber Cancer Institute in Boston, MA. Indeed, the Pew Research Center reports that 53% of women in their early 40s in 1994 had their first child by age 24, but this number dropped to 39% by 2014, and the trend appears to be continuing. “Because the risk of breast cancer tends to increase in one’s thirties and this corresponds with the time when women are becoming pregnant, we are seeing more cases than in years past.”
Wondering or worried about breast cancer diagnosis during pregnancy? We asked the experts about treatments that are safe during this time and what else women should consider.
How Breast Cancer Is Diagnosed During Pregnancy
During pregnancy, your body undergoes changes—your uterus expands, your heart pumps more blood, and your breasts undergo changes to prepare for milk production and breastfeeding. It’s these breast changes in particular that can make it difficult to catch a lump that may be cancerous during pregnancy.
“It can be challenging to diagnose because in pregnancy there are many normal physiologic changes that happen to breast tissue that can mimic the sensation of having a lump in the breast,” Dr. Mayer says. Plus, women who are pregnant are sometimes too young to routinely be getting screened for breast cancer with mammograms—while the U.S. Preventive Services Task Force (USPSTF) has recently called for routine mammograms to start at age 40, the current recommendation is to start receiving them at age 50 for women who are average risk, according to the Centers for Disease Control and Prevention.
That said, if you do feel any new lump in your breast tissue during pregnancy that doesn’t go away, it’s always wise to bring it to the attention of your doctor, says Dr. Mayer. It may be nothing serious, but it’s better to be safe and get it checked out.
Your doctor will examine the breast and may perform a biopsy, taking a sample of the breast tissue with a needle to test for cancerous cells, according to the American Cancer Society (ACS). If the results are unclear, your doctor may suggest minor surgery to remove a larger sample.
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Your doctor may also need to do imaging tests like a breast ultrasound or mammogram. Although mammogram uses a small amount of radiation, it is focused on the breast area, so it is thought to be safe during pregnancy, according to the ACS. Your health care provider will place a lead shield over your belly for further protection for your baby.
MRIs are not used as often during pregnancy. “For an MRI in the breast to really show things, we need to use contrast [dye], and we try to avoid that during pregnancy,” explains Jennifer K. Litton, M.D., a breast oncologist at MD Anderson Cancer Center in Houston, TX. Contrast dye is injected in the blood to help make the images taken during MRI more useful, but it’s been linked to abnormalities in the fetuses of lab animals, so doctors don’t usually recommend it during pregnancy, the ACS says.
Based on the results of your testing, your doctor will be able to determine whether you have breast cancer and learn more about your specific tumor, including the type of breast cancer and how advanced it is, as this information helps determine the most effective treatments.
Treatment for Breast Cancer During Pregnancy
If you find out you have breast cancer during pregnancy, it’s likely that your first concern will be the health of your growing baby. Reassuringly, just having breast cancer is not thought to be harmful to a fetus, and the cancer cannot spread to the baby, says Dr. Mayer. “However, if a mother is diagnosed with breast cancer in pregnancy and does not receive appropriate treatment, the cancer could worsen and create substantial health issues for her, so it’s important that it is appropriately treated in order to both optimize the health of the mother and protect the health of the baby.”
Once breast cancer is diagnosed, you and your health care team will work together to make a treatment plan. The treatments your doctor recommends will depend on several factors, including the type of breast cancer you are diagnosed with, the stage of your cancer, and how far along you are in your pregnancy. Thankfully, there are several options that can effectively treat breast cancer during pregnancy and that are safe for you and your baby.
“If a woman gets treated in a timely fashion with similar therapies used in non-pregnant breast cancer patients, we do not see differences in responses to treatment or in survival,” says Dr. Litton. There is also no evidence that ending a pregnancy will improve overall survival or cancer outcomes, according to the ACS.
That said, there are some limitations to what types of treatments can be safely used during pregnancy. Here’s what you need to know about the different treatment types for you and your baby.
Surgery During Pregnancy
While some physicians try to avoid surgery before the first trimester, surgical treatment can generally be performed safely in any trimester of pregnancy, Dr. Mayer says. In pregnant women with breast cancer, surgery is often used to remove the whole breast affected by cancer, according to the NCI, along with nearby lymph nodes under the arm. In some cases, it may also be an option to remove just the cancerous area and preserve the rest of the breast. What about anesthesia and other sedation medications used during surgery? According to researchers, they’re generally safe for the baby, with no increase in risk for birth defects. For some women, surgery is followed by other forms of treatment to ensure all cancer cells are killed, the NCI says.
Chemotherapy During Pregnancy
Several treatments, like different chemotherapies, are safe during only the second and third trimesters of pregnancy due to potential risk for birth defects when used earlier. “The first trimester is when much of the fetus’ organ development is going on, so our systematic therapies that affect the whole body can only be offered in the second or third trimester after organ development is complete,” Dr. Mayer explains. After the first trimester, chemo has not been shown to have any negative impact on the health of the pregnancy, she says.
Radiation Therapy During Pregnancy
Some treatments are not safe at any point in pregnancy and are typically delayed until after you give birth. Radiation therapy is one of these, says Dr. Litton. Potential risks of radiation therapy may include miscarriage, birth defects, slow growth of the fetus, and increased risk of childhood cancer, per the ACS.
Hormone Therapy During Pregnancy
Hormone therapies, including anti-estrogen therapies, anti-HER2 therapies, and others, can be highly effective in treating certain types of breast cancer—but they should not be used until after delivery because of potential harm to the pregnancy, says Dr. Litton. For example, a study in The Oncologist reported a high rate of severe birth defects in babies of pregnant women who used tamoxifen, a commonly used breast cancer drug that works by blocking the growth-stimulating effects of estrogen on some breast cancer tumors. For women who are diagnosed prior to becoming pregnant, research has found that pausing long-term use of hormone therapy used to treat breast cancer to allow time for a woman to get pregnant and have a baby appears to be safe and does not increase the risk that cancer will return, according to the NCI.
Breastfeeding With Breast Cancer
Another common question pregnant women with breast cancer who do not have surgery to remove their breasts have is whether they will be able to safely breastfeed after the baby is born. This depends on your specific disease and treatment course, Dr. Mayer says. “Some patients can finish all their breast cancer treatment before a baby is delivered, and if that’s the case, there may be time to breastfeed after delivery,” she says. “Other patients may need to take additional medications after delivery, such as endocrine therapies, that are not compatible with breastfeeding at the same time.”
In general, your doctor will likely recommend that you not breastfeed if you are going to continue or start breast cancer treatment in the postpartum period. This is because many breast cancer medications, including chemotherapies, hormone therapies, and targeted therapies, can be passed onto the baby through your breast milk, according to the ACS. Even after stopping these treatments, it can take several months for this risk to go away.
Getting Pregnant Again After Breast Cancer
And now for a little good news: Research is promising for women who want to get pregnant again in the future after breast cancer. Dr. Litton says studies of large groups of women who have had breast cancer don't show any ill effects on their health (or future babies) should they have another child.
Your doctor may recommend you wait two to three years after a diagnosis of breast cancer before getting pregnant again, she says. “There are a couple of reasons for this, including that some of that data suggests the further out [the mother] is from the time of diagnosis to the start of a new pregnancy, the less likely it is to change any survival issues [for the mother or child]. For people with some of the more aggressive tumor types that tend to recur in the first year or two, it can be really complicated if you are newly pregnant and in treatment as well.”
That said, it isn’t a “one-size-fits-all” approach, she says, and you should discuss any concerns about future family building with your health care team.
Additionally, it’s important to know that some forms of breast cancer treatment may have a temporary or permanent impact on your fertility. Before starting a systemic breast cancer treatment after delivering your baby, talk with your health care providers about how those treatments may affect your ability to get pregnant in the future and whether fertility preservation, like egg freezing, is an option you should explore, Dr. Litton recommends.
The Bottom Line
Getting a diagnosis of breast cancer while pregnant can lead to fears about the health of you and your baby. But prompt treatment can help protect your health and that of your pregnancy. Work with your health care team to explore options for treatment that are safe for you and your baby depending on your specific health factors.
“Caring for patients with breast cancer in pregnancy requires a multidisciplinary team that includes oncologists, obstetricians, fertility specialists, social workers, and other health care professionals,” Dr. Mayer says. “Everyone should work together to provide the best possible care.”
