Cancer during pregnancy is infrequent. It presents an ethical dilemma—remission may be obtained with chemotherapy, but it has potential harmful effects to the fetus. We report a case of a very low birth weight preterm female infant born to a 21-year-old mother diagnosed with leukemia and given chemotherapy up to 1 week before delivery. In the laboratory, initial findings included severe pancytopenia, and bone marrow aspiration demonstrated complete aplasia. She was given blood product transfusions, erythropoietin, and granulocyte colony stimulating factor. The hematologic derangement was resolved without documented infections. The second case is a preterm male infant whose 30-year-old mother was diagnosed with lymphoma and had received chemotherapy during the third trimester. The infant presented with moderate leukopenia. He had an uneventful course without documented infection. Exposure of the fetus to transplacental chemotherapy must be considered when evaluating therapy options and timing of delivery in hematologic malignancies diagnosed during pregnancy.