Baby showers, gift registries, nursery decorations, baby names and routine doctor’s visits. They are all things women expecting a child focus on. It’s a time of excitement and planning for the future. Cancer is the last thing a family wants to think about during pregnancy.

Still, a cancer diagnosis during pregnancy is a reality for one in every 1,000 women expecting a baby. It’s very rare, but it does happen.

Here Are 5 Things to Know

1. What’s the most common cancer found during pregnancy? Of all the cancers, breast cancer is diagnosed most while women are pregnant. Breast cancer occurs in one in 3,000 pregnancies. According to the American Cancer Society, these cancers are also known to show up during pregnancy:
   • Cervical cancer
   • Thyroid cancer
   • Hodgkin lymphoma
   • Non-Hodgkin lymphoma
   • Skin cancer
   • Gestational trophoblastic tumor
2. What tests can detect cancer during pregnancy?
   Low-radiation tests (X-rays and MRI) are generally considered safe. Women thinking about cancer screening should talk to their doctor about tests that may be the best for them.
3. What happens when cancer is found during pregnancy?
   Doctors and patients have a lot to consider when deciding next steps after cancer diagnosis. Where is the cancer located? How far along is the pregnancy? What is the stage of cancer? All these aspects need to be explored. It’s likely that a team of cancer experts and other doctors will work together to find the best treatment options to keep the mother and baby safe.
4. What cancer treatments available during pregnancy?
   
   
   • Surgery is an option when a tumor needs to be removed from healthy tissue. Anesthesia used during surgery could present some risks for the developing baby. The anesthesiologist, surgeon and high-risk obstetrician will decide the safest drugs for both mother and baby.
   • Chemotherapy drugs kill cancer cells and stop others from growing and spreading. The chance of harm to the baby depends on the drug and the stage of pregnancy. There is a chance of harm if chemotherapy is given in the first three months of pregnancy when vital organs are still developing.
   • Radiation therapy uses high-energy X-rays to destroy cancer cells. Risks to the baby depend on the dose and the area of the body being treated. Cancer is a serious illness that calls for teamwork between the patient and doctors.
5. How will cancer affect pregnancy?
   In the first trimester, treatment can be risky. For example, chemo may cause birth defects or pregnancy loss. Testing, though, shouldn’t harm the baby. After the first trimester treatment has far less severe risks, but there is a chance that the baby could be born early or be small for its age.
   
   Once the baby is born, cancer treatment can continue. Breastfeeding isn’t a good idea for women undergoing chemotherapy.

If you are pregnant and dealing with cancer, it’s important to have a support system of friends and family. Surround yourself with positive people who can attend doctor’s appointments to listen or take notes during the visit.

Sources: Cancer During Pregnancy,  Cancer.net, 2020; 5 Things You Need to Know About Cancer During Pregnancy,  National Foundation for Cancer Research, 2019

Originally published 1/15/2016; Revised 2020, 2023