PATHOPHYSIOLOGY, CLINICAL PRESENTATION, PREVENTION, AND TREATMENT OF OVARIAN HYPERSTIMULATION SYNDROME – AN UPDATE FOR CLINICIANS

Ovarian hyperstimulation syndrome (OHSS) is a complication of ovarian stimulation, mostly performed with gonadotropins, during controlled ovarian hyperstimulation (COH) for assisted reproduction technology as well as other infertility treatments. The main pathophysiological mechanism of OHSS is increased vascular permeability, resulting a shift of serum from the intravascular space to the third space. The consequences include excess fluid in the third space (abdominal, pleural, and pericardial cavities) and haemoconcentration with reduced organ perfusion and hypercoagulability. Primary prevention of OHSS is to identify high-risk patients and to apply adequate prevention measures such as the use of gonadotropin-releasing hormone (GnRH) antagonist protocol for COH, individualized and modest gonadotropin dosing, the use of a GnRH agonist to trigger oocyte maturation before oocyte retrieval in high-risk patients, the use of medications such as cabergoline and metformin to prevent OHSS in high-risk patients, elective cryopreservation of all embryos and their subsequent transfer in non-stimulated cycles in patients at risk for OHSS, and in vitro maturation. The primary treatment approaches for OHSS include fluid management and thromboprophylaxis.