This paper reports treatment with combined chemotherapy during pregnancy. A 39-year-old woman with breast cancer was given adjuvant chemotherapy including cyclophosphamide, methotrexate and 6-fluorouracil from the 6th to the 24th week of gestation. The possibility of teratogenic effects on the fetus was explained to the patient however she refused to terminate the pregnancy. A 30-week male infant with only a minor malformation was delivered. The authors reviewed the literature regarding chemotherapeutic agents given during the first trimester of pregnancy. Most cytotoxic drugs have teratogenic effects on experimental animal subjects. However, actual data on human fetuses are sparse because of the variety of therapeutic regimens and the rarity of administering chemotherapy during pregnancy. The long-term effects of exposure to cytotoxic drugs in utero, needs further research.