This page was reviewed under our medical and editorial policy by
Ruchi Garg, MD, Chair, Gynecologic Oncology, City of Hope Atlanta, Chicago and Phoenix
This page was reviewed on November 17, 2021.
Cancer during pregnancy is rare, with fewer than 1 percent of all cancer diagnoses affecting pregnant women. When it does occur, diagnosing and treating cancer during pregnancy is complicated for many reasons. While the cancer itself doesn’t usually affect the unborn baby, any testing and treatments need to be done carefully to ensure a safe pregnancy. Cancer treatment plans may be adjusted for pregnant women, but some aspects are risky for the fetus, so doctor and patient need to discuss the pros and cons.
Typically, the earlier in pregnancy cancer treatment begins, the more risks are involved. Still, if cancer is suspected, pregnant women shouldn’t hesitate to speak with their doctor as soon as possible to clarify the situation and create a safe treatment plan.
A cancer diagnosis during pregnancy may feel devastating and scary, but it may help to speak with other women who have gone through it and benefited from treatment. Oncologists may recommend cancer support groups to help patients connect with others who have fought and beaten cancer during pregnancy. Having a support network may help patients process their emotions while preparing for the potential logistical challenges ahead.
While cancer during pregnancy isn’t common, it can occur. The best way to prevent or catch the cancer early is for patients to pay attention to their bodies and keep their doctor updated about symptoms.
The most common cancer types diagnosed during pregnancy are:
Cancers of the reproductive system are especially challenging to treat during pregnancy because they originate in the areas near the fetus.
One of the difficulties in diagnosing cancer during pregnancy is that many symptoms may be misidentified as pregnancy symptoms. This may lead to a delay in diagnosis. Even if testing is done properly, pregnancy may interact with the results of diagnostic tests, sometimes producing false-negative cancer results.
Some standard tests for cancer can’t be done during pregnancy, such as blood testing for tumor markers. Tumor markers are substances in the body that may point to the presence of cancer. Pregnancy, however, renders most of these tests ineffective because these substances are in flux, so doctors may seek more accurate testing methods.
Early diagnosis offers the best prognosis for anyone who has cancer, including pregnant women. Patients who suspect they’re pregnant should notify their doctors ahead of time to ensure the necessary precautions are in place.
Following are some of the tests that may help the care team make a cancer diagnosis in pregnant patients.
Ultrasound: If symptoms are consistent and the doctor recommends testing for cancer, then an ultrasound is usually the preferred method, as it’s safe for pregnant women. However, not all cancers may be diagnosed this way.
Magnetic resonance imaging (MRI): Diagnostic tests depend on the type of cancer suspected and the risks involved for the unborn baby. Testing that uses any radiation, for instance, may be risky and unsafe for the fetus, so doctors may recommend delaying it until after birth if possible. An MRI, on the other hand, is considered safe during all stages of pregnancy, making it a good testing option.
Other diagnostic tests: Doctors may elect to perform other diagnostic tests or procedures such as a biopsy, endoscopy, bone marrow aspiration or lumbar puncture for certain types of cancer. They’ll administer sedatives, if needed, in the way that’s safest for the pregnancy.
After a cancer diagnosis, the next step is to connect with the right specialized oncologist, who may work in coordination with an obstetrician-gynecologist throughout the pregnancy and after delivery, too.
Treatment plans for pregnant patients depend on many factors, including:
While treating cancer as early as possible is the approach most often used with people who aren’t pregnant, it’s often advised that women wait until their second trimester of pregnancy to begin treatment, since the first few months are crucial for the development of the fetus. For patients with early-stage cancer, doctors may even recommend delaying treatment until after the baby is born.
Typically three treatment options are available, depending on the cancer diagnosis: surgery, chemotherapy and radiation therapy. Each presents its own sets of challenges for pregnant women.
Surgery is usually safe, as are anesthetics, but it’s typically delayed until the second trimester (after the first 12 weeks). Surgery may also become difficult to perform late in the pregnancy.
Chemotherapy is often delayed until the second trimester. It isn’t recommended after 35 weeks or later either, as it may trigger labor or lower the patient’s blood cell counts, leading to bleeding or increasing the chance of infection.
Radiation therapy is difficult to perform on pregnant women due to the risk of exposing the fetus to radiation. It shouldn’t be given at all in the first trimester. Doctors may recommend waiting on radiation therapy until after the patient gives birth, depending on the location of the cancer in relation to the baby and the stage of the cancer.
Hormone therapy shouldn’t be given at all during pregnancy.
Keeping the mother healthy is just as important as keeping the unborn baby healthy. Unfortunately, cancer during pregnancy may pose many risks to both. While cancer may not directly impact the fetus, it may be detrimental to the woman diagnosed, especially if the cancer has reached an advanced stage. Doctors typically have to weigh two major factors: the benefit to the patient’s health and the risk to her unborn baby.
If the cancer has spread, or metastasized, the patient may require immediate treatment for the best chance of survival. This, unfortunately, may pose risks to the fetus. Ending a pregnancy early is not usually advised unless the mother’s health is in critical condition. It’s important for the patient to discuss the risks with her cancer care team, so she fully understands the options.
Being pregnant and undergoing cancer treatment are both difficult on their own, but the combination may feel stressful and overwhelming. Mental well-being is crucial. Whether the patient joins a support group or visits a therapist, it’s important to prioritize emotional health just as much as physical health.
Several well-known risks are associated with cancer treatment during pregnancy.
The safety of chemotherapy during pregnancy may depend on when it’s administered. Chemotherapy treatment given in the first trimester may affect the baby's eyes, ears and blood system, and may impact fetal growth. In the second and third trimesters, chemotherapy poses a lower risk to the fetus, and the placenta is typically effective in protecting the baby from the drugs.
The outlook depends on the specific cancer, as certain cancers may be treated more easily during pregnancy than others. Breast cancer is the most common cancer diagnosed during pregnancy, and pregnancy doesn’t appear to affect the woman’s cancer outcome. Cervical cancer, though, may be more complicated because the cancer is in close proximity to the growing fetus. In such cases, a Cesarean section (C-section) is often required to protect both mother and baby.
The earlier doctors catch the cancer tumor or cancer cells, the more options the patient has. Women diagnosed in advanced stages may have difficult decisions to make to ensure the best possible outcome.
Treatment is typically best performed during the second and third trimesters of pregnancy. This offers the best outcome for the baby. However, this may not be an option for everybody, which is why patients should discuss all options with their doctor before starting any cancer treatment.
There’s no one-size-fits-all approach to cancer treatment. An expectant woman may need to change her birth delivery plan, undergo additional procedures she wasn’t expecting, and make tough decisions along the way. The best thing for a patient to do is to mentally prepare and—surround herself with a network of friends and family, and her care team, who can support her during and after pregnancy.