Topic Overview

On rare occasions, cancer coincides with pregnancy. Because the medicines and radiation used for treating cancer can be dangerous to a fetus, a pregnant woman and her doctors must weigh a number of factors when planning her care, including:

• The fetus's gestational age.
• The type and location of the cancer.
• How advanced the cancer is.
• How rapidly the cancer is developing.
• Whether she has other health problems.

In nonpregnant women, surgery may be used to remove cancer, depending on the cancer's type and location. After surgery to remove cancer, radiation, chemotherapy, or a combination of the two may be used to kill any remaining cancer cells. When treating a pregnant woman, doctors adjust the usual treatment regimen with the following in mind.¹

• Radiation therapy for cancer treatment is not usually used during pregnancy because in can be harmful to the baby.
• Diagnostic tests that use radiation may be used during pregnancy if necessary. But ultrasound and magnetic resonance imaging (MRI) are considered safer and are used whenever possible.
• Chemotherapy medicines are not usually used during the first trimester because of the risks to the fetus, but there are some that may be safely given in the 2nd and 3rd trimesters of pregnancy.

Whenever possible, doctors try to delay chemotherapy during pregnancy to minimize the effects on the fetus. Such decisions depend on how advanced the cancer is and how quickly it is developing.

• If cancer is diagnosed in the third trimester, it may be possible to first deliver the baby, then start treatment. Once the fetus's lungs are mature, as confirmed by amniocentesis, an early cesarean or induced delivery can shorten the wait till treatment.
• If cancer is diagnosed in the first or second trimester, your doctors may try to delay chemotherapy as long into the second trimester as possible.
• If advanced cancer is diagnosed in the first trimester, and immediate radiation and chemotherapy are necessary, your doctor may recommend ending the pregnancy.

If you have been diagnosed with cancer during your pregnancy, you will be working with a number of health professionals. Ask your cancer specialist (oncologist) for the name of a licensed medical social worker who can help support you through your treatment. A social worker can also help coordinate the various professionals involved with your care.