The aim of our study was to determine the efficacy of postponing administration of human chorionic gonadotropin while continuing daily gonadotropin-releasing hormone agonist therapy (‘coasting’) to prevent the occurrence of severe ovarian hyperstimulation syndrome (OHSS) for patients with polycystic ovary (PCO) syndrome. Five patients with PCO who had been hospitalized due to severe OHSS in previous in vitro fertilization and embryo transfer or intrauterine insemination cycles at the Tottori University Hospital were included in the study. The rates of mature oocytes and fertilization were comparable between the cycles. A singleton pregnancy was achieved in a patient during the coasting cycle, and none of the women developed severe OHSS in coasting cycles. The results suggest that coasting may be an alternative method for reducing the severity of OHSS in patients with PCO.