The Effects of Chemotherapy on Pregnancy

For a pregnant woman diagnosed with cancer, chemotherapy may be life-saving for her but could be life-threatening to the fetus. A woman can be faced with a devastating choice. Chemotherapy can't always be delayed until after delivery, depending on the type of cancer and stage of the disease. Women diagnosed with cancer who decide not to terminate the pregnancy but also decline chemotherapy may die along with the child who is unable to sustain life outside of the womb.

Trimesters

There can be safe use of chemotherapy--especially during the second and third trimester--without harming the woman with cancer and the baby, according to researchers at Cooper Health System in Camden, New Jersey and reported in Lancet Oncology on July 5, 2004. Exposure to chemotherapy during the first trimester of pregnancy has been associated with increased risk of major malformations of the fetus, reports the National Center for Biotechnology Information of the National Institutes of Health. Exposure in the second and third trimesters does not seem to cause these problems, but it can result in low birth weights. But the brain develops throughout pregnancy and might be affected later in pregnancy. Studies on the effects of pregnancy and chemotherapy are limited. Research on 89 pregnancies by the University of Texas M.D. Anderson Cancer Center in Houston found that fetuses exposed to chemotherapy in the second and third trimesters can be carried to term without congenital abnormalities and develop normally, it was reported in the Journal of the National Cancer Institute Monograph in 2005.

Time Factors

Many pregnant women terminate the pregnancy because a delay in treatment could harm the woman and ultimately the baby. Breast cancer can spread to other areas of the body because of delayed treatment. The risk of the disease spreading can increase as much as five to 10 percent, according to Health Information Directory, a health website. Many doctors have recommended terminating the pregnancy for women who need treatment. But that's changing as more evidence reveals chemotherapy may be safer in the second and third trimesters. Chemotherapy may also affect the immune system and lower the white blood cell count. Many doctors recommend the treatments be stopped a month before delivery.

Fertility

There are concerns about chemotherapy causing fertility problems, explains the National Cancer Institute. Women older than 35 to 40 years are the most susceptible to the ovarian effects of chemotherapy. The doses received may also be a factor. Younger women can tolerate greater doses. It's difficult to determine the outcome for each individual. However, the treatment doesn't appear to be a risk to future offspring of women when they're treated before pregnancy. Doctors are learning that some chemotherapy drugs are better than others for pregnant women. Methotrexate is a risky chemotherapy drug for these women because it has been known to cause birth defects and miscarriages.