LAUSR

The purpose of this review is to analyze current medical strategies in the prevention of ovarian hyperstimulation syndrome (OHSS) during ovarian stimulation for in vitro fertilization. Owing to contemporary preventive measures of OHSS, the incidence of moderate and severe forms of the syndrome varies between 0.18% and 1.40%. Although none of medical strategies is completely effective, there is high-quality evidence that replacing human chorionic gonadotropin (hCG) by gonadotropin-releasing hormone (GnRH) agonists after GnRH antagonists and moderate- quality evidence that GnRH antagonist protocols, dopamine agonists and mild protocols reduce the occurrence of OHSS. Among various GnRH agonists, buserelin 0.5 mg, triptorelin 0.2 mg and leuprolide acetate (0.5-4 mg) have been mostly utilized. Although GnRH trigger is currently regarded as the best tool for OHSS prevention, intensive luteal support with exogenous administration of estradiol and progesterone or low-dose hCG on the day of oocyte retrieval or on the day of GnRH agonist trigger are required to achieve optimal conception rates due to early luteolysis. Among currently available dopamine agonists, cabergoline, quinagolide and bromocriptine are the most common drugs that should be used for prevention of both early and late OHSS. Mild stimulation protocols offer attractive option in OHSS prevention with satisfactory pregnancy rates.