Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic and life threatening syndrome with abdominal pain nausea vomiting bloating ascitis and sometimes with end organ damage resulting from excessive ovarian stimulation. The reported incidence of OHSS varies from 1% to 10% of in vitro fertilization cycles. Although ovarian hyperstimulation syndrome has been known for many years it has been treated empirically and the underlying causes have been poorly understood. In order to reduce the risk of OHSS several approaches have been proposed. One common technique is to coast the patient. In coasting gonadotropin stimulation is withheld and E2 levels are permitted to decrease before hCG is administered. Another technique is elective cryopreservation of all embryos plans to reduce the risk of OHSS by subsequent transfer of embryos in non-stimulated cycles. The present study compares the outcome of preventive strategies of ovarian hyperstimulation syndrome in ART cycles.