Transient neonatal myelosuppression (TNM) is a rare but potentially life-threatening adverse effect of fetal exposure to maternal chemotherapy during pregnancy. We report a case of TNM in a preterm infant born to a mother diagnosed with acute lymphoblastic leukemia during pregnancy. The mother received chemotherapy during the second and third trimester. The neonate was successfully treated with supportive care. In addition, we also conducted a medical literature review and identified another 14 cases of TNM. Although the long-term outcome of these children is not known, short-term survival is relatively good. Prompt recognition and aggressive treatment of infants at risk for TNM is mandatory. Copyright (C) 2008 S. Karger AG, Basel