Abstract

Ovarian hyperstimulation syndrome (OHSS) is the most serious iatrogenic disorder resulting from ovarianstimulation during assisted reproductive techniques (ARTs). It can result in renal failure, thromboembolic phenomena,adult respiratory distress syndrome and, occasionally, death. Almost all previous preventive strategies resulted ineffective. Vascular Endothelial Growth Factor (VEGF) plays a pivotal role in the pathophysiology of this syndrome so VEGFantagonism has been suggested for OHSS prevention. Since VEGF is also a physiological regulator of folliculogenesis,progesterone secretion and endometrial angiogenesis, its complete inactivation by monoclonal antibodies could producepotential undesirable effects. Administration of Human Chorionic Gonadotropin (HCG) stimulation of VEGF productionis fatal for the developing of OHSS; the use of GnRH agonist instead of HCG for ovulation triggering, is a promisingstrategy. Recently dopamine D2 agonists have been shown to counteract VEGF induced vascular permeability. The lack oftoxic or teratogenic effects could make cabergoline an effective and safe aetiological approach for OHSSprevention/treatment. A recent meta-analysis has indicated that the administration of metformin significantly preventsOHSS development in polycystic ovary syndrome, an high risk group. In the light of these new studies we believe that recent guidelines on OHSS prevention need a substantial revision.

Keywords: OHSS, VEGF, HCG, GnRH antagonists, cabergoline, metformin