Chemotherapy in pregnancy.

One in 1000 pregnancies is complicated with cancer with the most common tumors being breast cancer, cervical cancer, thyroid, leukemia, lymphoma, and ovarian cancer. It is often assumed that cancer during pregnancy necessitates sacrificing the well-being of the fetus but in most cases appropriate treatment can be offered to the mother without placing the fetus at serious risk. The care of a pregnant woman with cancer involves evaluation of competing maternal and fetal risks and benefits. Although it is rare to administer chemotherapy during pregnancy, the risks depend on the drugs used and the gestational age of the fetus. During the period of organogenesis (4 to 13 wk), administration of cytotoxic drugs carries an increased risk of fetal malformations and fetal loss. Chemotherapy in the second or third trimester is associated with intrauterine growth retardation, prematurity, and low birth weight and bone marrow toxicity in many exposed infants.