What Kind of Effects Does Chemotherapy Have on a Fetus?

Pregnancy is an exciting time in a woman's life. Unfortunately, pregnancy does not make a woman immune to cancer. Cancer treatment may have negative effects on her growing baby, but delaying treatment until after birth could be deadly. The health of both the woman and the fetus are factors that will weigh in on her choices, and whether chemotherapy is a good option at this time.

Chemotherapy

• Most drugs used in chemotherapy have been proved to cause damage to rapidly developing cells, such as bone marrow. Studies in animals have suggested that fetuses could be affected in a similar way, resulting in birth defects or spontaneous abortions.

First Trimester

• Chemotherapy is not recommended during the first trimester of pregnancy. Birth defects are more likely at this time; other potential side effects include hemorrhaging, infection and reduced platelet and red and white blood cell counts for the fetus.

Second and Third Trimesters

• There are no known risks of birth defects or mental retardation in fetuses that are exposed to chemotherapy during the second and third trimesters. While brain development has the potential to be affected, because the brain develops throughout the course of pregnancy, there has been no evidence of such. Major malformations are unlikely to be a problem, but other problems, such as low birth weight, could result.

Trying to Conceive

• Women who survive cancer are advised to wait two years after treatment before trying to conceive. Most relapses occur during that period, so waiting to conceive can help prevent the need to terminate the pregnancy or delay cancer treatment due to the potential effects on the fetus.

Treatment

• Little is known about how chemotherapy can affect fetuses, so cancer treatment while pregnant should be discussed in detail with your doctor. Other forms of treatment, such as surgery or radiation therapy, may be safer for your fetus.