Cancer During Pregnancy

Approved by the Cancer.Net Editorial Board, 05/2018

Cancer during pregnancy is uncommon. But when it does occur, it can be complicated for the mother and the health care team. Cancer itself rarely affects the growing baby directly. But doctors must be selective about how they diagnose and treat pregnant women with cancer. Therefore, it is important to find a health care team who has experience treating cancer in pregnant women. Learn more about finding an oncologist.

Types of cancers that occur during pregnancy

Breast cancer is the most common cancer diagnosed during pregnancy. It affects about 1 in 3,000 women who are pregnant. Breasts typically enlarge and change texture during pregnancy. So changes from cancer may be difficult to detect. Or the breast changes may not appear to be abnormal. This means pregnant women with breast cancer may be diagnosed later than women who are not pregnant.

Other cancers that tend to occur during pregnancy are also more common in younger people:

Diagnosing cancer during pregnancy

Being pregnant may delay a cancer diagnosis. This is because some cancer symptoms, such as bloating, headaches, breast changes, or rectal bleeding, are also common during pregnancy. But pregnancy can sometimes uncover cancer. For example, a Pap test done as part of standard pregnancy care can find cervical cancer. And an ultrasound performed during pregnancy could find ovarian cancer.

Some diagnostic tests for cancer are safe for pregnant women and the fetus. But others could be harmful:

  • X-ray. Research shows that the level of radiation in diagnostic x-rays is too low to harm the fetus. When possible, women can use a lead shield that covers the abdomen during x-rays.

  • Computed tomography (CT or CAT) scans. CT scans are similar to x-rays but are much more accurate. They can diagnose cancer or show whether the cancer has spread. CT scans of the head or chest are usually safe during pregnancy. This is because they do not directly expose the fetus to radiation. When possible, women can use a lead shield that covers the abdomen during CT scans. CT scans of the abdomen or pelvis should be done only if absolutely necessary and after talking with your health care team.

  • Other tests. Magnetic resonance imaging (MRI), ultrasound, and biopsy are generally safe during pregnancy.

Cancer treatment during pregnancy

Planning treatment during pregnancy requires a multidisciplinary team of doctors working together. This includes cancer doctors and high-risk obstetricians. An obstetrician is a doctor who cares for a woman during and shortly after pregnancy. Cancer doctors and obstetricians:

  • Compare the best cancer treatment options for the woman with the possible risks to the growing baby.

  • Consider a number of factors, including:

    • Stage of the pregnancy

    • Type, location, size, and stage of the cancer

    • The wishes of the woman and her family

  • Closely monitor the woman during treatment and make sure the baby is healthy.

Sometimes doctors choose to delay or avoid certain treatments for pregnant women with cancer. For example:

  • During the first 3 months of pregnancy, some cancer treatments are more likely to harm the fetus. So the health care team may delay treatment until the second or third trimesters.

  • When cancer is diagnosed later in pregnancy, health care providers may wait to start treatment until after the baby is born.

  • In other cases, such as early-stage cervical cancer, the health care team may wait to treat the cancer until after delivery.

  • Some treatments can harm the fetus in all trimesters. And health care providers generally avoid using these treatments during pregnancy. For example, radiation therapy uses high-energy x-rays to destroy cancer cells. The risks to the developing baby depend on the radiation dose and the area of the body being treated.

Treatments that may be used during pregnancy

Some cancer treatments can be used during pregnancy:

  • Surgery. During surgery, doctors remove the tumor and some of the surrounding healthy tissue. This poses little risk to the growing baby. It is also considered the safest cancer treatment during all stages of pregnancy.

  • Chemotherapy. Doctors use chemotherapy to destroy cancer cells. But your health care team may choose to use this treatment only during certain times in pregnancy:

    • During the first 3 months of pregnancy, chemotherapy carries risk of birth defects or pregnancy loss. This is when the fetus's organs are still growing.

    • During the second and third trimesters, doctors can give several types of chemotherapy without apparent risk to the fetus. The placenta acts as a barrier between the woman and the baby, so some drugs cannot pass through. Other drugs can pass through only in small amounts. Studies suggest that babies who are exposed to chemotherapy while in the mother’s uterus do not show abnormalities immediately after delivery or during growth and development compared with babies not exposed to chemotherapy.

    • Chemotherapy in the later stages of pregnancy may cause side effects in the woman. This may indirectly harm the baby. A possible side effect is low blood counts during delivery, which can increase risk of infection.

    • Some health care providers may discuss inducing labor early to protect the baby from cancer treatment. But it is preferred to continue the pregnancy until natural labor and delivery occurs. Babies born early may have a higher risk of health problems than babies born at term who are exposed to chemotherapy.

    • Women who are receiving chemotherapy after a pregnancy should not breastfeed. Chemotherapy can transfer to the infant through breast milk.

How pregnancy affects cancer risks

Pregnancy itself does not appear to affect how well the cancer treatment works. But if a woman's diagnosis or treatment is delayed due to pregnancy, the cancer may have a larger effect. And this may lead to more risks associated with the cancer. Talk with your health care team about how pregnancy may affect your cancer risk and recovery from therapy.

Questions to ask the health care team

If you are pregnant and have recently been diagnosed with cancer, consider asking your health care team these questions:

  • How much experience do you have treating pregnant women with cancer?

  • How will you work with my obstetrician?

  • Do I need to have any special tests done?

  • Which treatment plan do you recommend? Why?

  • Do I need to begin treatment right away, or should I wait?

  • Could delaying treatment affect my chance of recovery?

  • Is it safe to continue the pregnancy?

  • What are the short- and long-term risks of my treatment plan to me? To the baby?

  • How will my treatment affect my delivery?

  • Will I be able to breastfeed?

  • What support services and other resources are available to me and my family?

Related Resources

Fighting for Henry: My Story of Cancer and Pregnancy

Having a Baby After Cancer: Pregnancy

Having a Baby After Cancer: Fertility Assistance and Other Options

More Information

Hope for Two: The Pregnant with Cancer Network

Pregnancy and Cancer Registry

MedlinePlus: Tumors and Pregnancy

National Cancer Institute: Breast Cancer Treatment During Pregnancy