The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What is cancer?

In the normal body, cells are constantly growing, dividing, making new cells, and then dying in a very orderly fashion. In adults, this is done to replace cells that have died or are worn-out in order to repair injuries that have occurred. Cancer occurs when abnormal cells in the body begin growing out of control and spread to other tissues, which normal cells dont do. For most people with cancer, the reason why cells suddenly begin doing this is unknown.

During pregnancy, the most common types of cancer are found in the breast, uterus, thyroid, and blood (Hodgkins lymphoma and leukemia). For most of these, the outcomes are similar in pregnant women compared to non-pregnant women of the same cancer stage. However, it is not uncommon for pregnant women to be diagnosed with more advanced stages of cancer for a variety of reasons. This can complicate treatment and affect long-term survival.

In the past, termination of the pregnancy was usually recommended if cancer was diagnosed during pregnancy. New evidence shows that most pregnancies can be continued safely without affecting the moms survival and without causing significant problems for the developing baby, if treatment can be delayed until after the first trimester.

How common is cancer during pregnancy?

Cancer is rare during pregnancy, complicating an estimated 0.02 to 0.1% of pregnancies per year. Breast cancer is estimated to occur in 1 in 3,000 pregnancies, while certain types of leukemia have only been reported in 100 pregnancies.

How is cancer during pregnancy diagnosed?

In general, cancer is diagnosed the same way in pregnant women as it is in non-pregnant women. Biopsies are usually done to confirm a cancer diagnosis and are safe to do while pregnant. Once a cancer has been diagnosed, the next step is to determine which stage or how advanced it is . Staging of the cancer frequently involves x-ray, CT scans, MRI, PET-CT, or surgery. When x-rays are performed during pregnancy, your abdomen is shielded to prevent exposing the developing baby to x-rays. CT scans and MRI can be safely done in pregnancy but their use should be limited. PET-CT scans should not be perforned while you are pregnant. Surgery is also safe to do during pregnancy, but it is safest during the second trimester.

Does cancer cause problems during pregnancy?

Cancer doesnt appear to cause an increase in pregnancy complications. However, if treatment with chemotherapy is given during the first trimester, the risk of miscarriage increases.

Does cancer during pregnancy cause problems for the baby?

Cancer does not appear to cause problems for the baby but the treatment for the cancer can. The chemotherapy and radiation that are used to treat cancer can cause birth defects in about 15% of babies and low birth weight in about 40% of babies. The risk for birth defects is highest when treatment is given during the first trimester. Some chemotherapy drugs are toxic to the babys developing brain and can lead to mental retardation that is not noticed until they are older. Chemotherapy can lower the babys white blood cells and red blood cells most noticeably a few weeks after receiving chemotherapy. Therefore, it is recommended to not deliver the baby for at least 2 to 3 weeks after receiving chemotherapy.

What to consider about taking medications when you are pregnant or breastfeeding:

  • The risks to yourself and your baby if you do not treat the cancer
  • The risk of the cancer returning if you stop taking your medication or if you switch to a different medication.
  • The risks and benefits of each medication you use when you are pregnant
  • The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat cancer during pregnancy?

The type of cancer that you have will determine which type of treatment you will need, but all chemotherapy drugs are harmful to the developing baby if they are used during the first trimester. Because of this, if your cancer is diagnosed during the first trimester, evidence is available to support waiting to start cancer treatment until the second or third trimester, if you have a slow-growing cancer. Not giving chemotherapy during the first trimester reduces the risk of birth defects known as side effects of these drugs. You will need to have very close monitoring of the cancer to make sure that it is not progressing when treatment is delayed. For these slower-growing tumors, survival rates are not affected by delaying treatment. However, there are certain types of cancers that are more aggressive and waiting to begin treatment will not be an option. In these situations, terminating the pregnancy may be needed to begin life-saving treatment. It is important to talk with your cancer specialist about these options.

Who should NOT stop taking medication for cancer during pregnancy?

In general, once treatment for cancer is begun, it should not be stopped.

What should I know about choosing a medication for my cancer during pregnancy?

Since cancer in pregnancy is rare, there are limited data available about the risks from chemotherapy on the developing baby and pregnancy. The data that are available show that chemotherapy may pose little risk to the developing baby when used during the second and third trimesters. It is generally recommended to avoid chemotherapy during the first trimester, when the babys organs are developing, because the risk of birth defects is highest at this time.

Birth defects that have been reported when chemotherapy is used during the first trimester include missing toes or fingers, abnormally developed arms or legs, abnormal facial features, heart defects, and  malformed kidneys. Miscarriages are also more common when chemotherapy is used during the first trimester. When chemotherapy is used during the second or third trimester, low birth weight is the most common side effect. Other side effects include elevated bilirubin causing jaundice and low levels of white blood cells and red blood cells.

You may find Pregistrys expert reports about the individual medications to treat cancer here. Additional information can also be found in the sources listed below.

What should I know about taking a medication for my cancer when I am breastfeeding?

In general, breast feeding while being treated with chemotherapy is not recommended because there is not enough information available to know if it is safe. There are a few exceptions to this, so it is recommended to discuss whether or not nursing is safe for you and your baby with your healthcare provider.

What alternative therapies besides medications can I use to treat my cancer during pregnancy?

There are no alternative therapies for cancer treatment that have been shown to be safe and effective.

What can I do for myself and my baby when I have cancer during pregnancy?

If you are diagnosed with cancer during pregnancy, it is important to talk with your cancer specialist and pregnancy care provider about the risks your particular cancer has on the pregnancy. Knowing if your cancer requires immediate, aggressive treatment or if treatment can safely be delayed until later in the pregnancy is important to help you decide if the pregnancy can safely be continued.

During the pregnancy and cancer treatment, it is important to keep yourself as healthy as possible. Eating a well-balanced diet, getting plenty of rest, and following all recommendations that your cancer specialist gives you is important. Regular exercise is
also recommended to improve your physical functioning and mood during treatment. Depression is not uncommon during pregnancy and with cancer treatment. Seeking out cancer support groups and counseling may help lessen depression symptoms. If you feel that you are developing depression, dont hesitate to discuss this with your health care provider so that a treatment plan can be made.

Resources for cancer during pregnancy:

For more information about cancer during and after pregnancy, contact (800-994-9662 [TDD: 888-220-5446]) or contact the following organizations:


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Last Updated: 07-09-2018
General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

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