Because breast cancer risk increases with age and women in the United States continue to delay childbirth, the incidence of breast cancer during pregnancy will rise. About 10% of patients younger than age 40 diagnosed with breast cancer are pregnant. Historically, labor-delivery and oncology, the two spheres of clinical care, rarely overlapped. However, breast cancer occurs in about 1 in 3,000 pregnancies. Case studies suggest that the administration of chemotherapeutic agents during the second and third trimesters may be safe for the mother and fetus. Three specific case studies of pregnant women with cancer who received treatment are presented to identify the issues of cancer during pregnancy. Outcomes of infants who received chemotherapy in utero and associated nursing implications also are explored.