New approaches in the prevention of ovarian hyperstimulation syndrome

Severe ovarian hyperstimulation syndrome (OHSS) is a rare and potentially life-threatening complication of ovarian stimulation for WF. The crucial issue about OHSS is prevention, rather than treatment. One factor to preventing OHSS is recognition of risk factors. Among risk factors such as polycystic ovarian syndrome (PCOS), rapidly rising serum estradiol levels during ovarian stimulation, and previous episodes of OHSS, the number of preovulatory follicles has been shown to have the highest sensitivity and specificity to identify the patients with subsequent development of OHSS. More recently, follicle-stimulating hormone (FSH) receptor polymorphisms and anti-muellerian hormone (AMH) have been suggested to be predictive in the development of the disease, but existing data are conflicting or insufficient. As none of the available clinical algorithms will identify all patients at risk of OHSS, future IVF treatment regimen should routinely employ means that reduce the incidence of the syndrome (GnRH-antagonist protocols, mild stimulation). However, no modification to current ovarian stimulation regimen will be 100% effective in preventing severe OHSS, therefore OHSS prevention by replacing the ovulation-inducing trigger of human chorionic gonadotropin (hCG) with a bolus dose of GnRH-agonist has recently attained great interest. Further novel concepts in OHSS incidence reduction, such as coasting with antagonist, reduced dose of hCG, administration of a VEGF receptor antagonist after oocyte pick-up, and luteal phase antagonist administration will selectively be discussed in this literature review.