Neonatal effects of breast cancer chemotherapy administered during pregnancy.

A human fetus is most susceptible to teratogenic agents during the first trimester of pregnancy. Cyclophosphamide and doxorubicin are pregnancy category D agents; however, potential benefits may warrant treatment with these agents during pregnancy under special circumstances. During her first trimester of pregnancy, a 37-year-old Caucasian woman was diagnosed with stage IIB infiltrating ductal carcinoma in situ (breast cancer) that was estrogen and progesterone receptor negative and human epidermal growth factor receptor-2 positive. The patient was treated with doxorubicin and cyclophosphamide in the second and third trimesters and delivered a premature baby boy at 31 weeks' gestation. The neonate was intubated on delivery because of respiratory distress and failure; however, no physical anomalies were observed. He had neutropenia and anemia, quite possibly as a result of his mother's chemotherapy 1 week before delivery. He was prophylactically treated for sepsis, but all cultures were negative. The infant grew and developed normally during his first year of life and remained in good health. An objective causality assessment revealed that it was probable that the infant's adverse events (prematurity, neutropenia, and anemia) were related to his mother's doxorubicin and cyclophosphamide therapy; however, these were the only adverse events potentially linked to in utero exposure to chemotherapy during the second and third trimesters. Due to the special considerations of both mother and infant, optimal treatment for patients with pregnancy-associated breast cancer requires the expert opinion of a multidisciplinary care team.