Purpose To review and discuss the pathophysiology and prevention strategies for ovarian hyperstimulation syndrome (OHSS), which is a condition that may occur in up to 20% of the high risk women submitted to assisted reproductive technology cycles. Methods The English language literature on these topics were reviewed through PubMed and discussed with emphasis on recent data. Results The role of estradiol, luteinizing hormone, human chorionic gonadotropin (hCG), inflammatory mediators, the renin-angiotensin system and vascular endothelial growth factor is discussed in the pathophysiology of OHSS. In addition we consider the prevention strategies, including coasting, administration of albumin, renin-angiotensin system blockage, dopamine agonist administration, nonsteroidal anti-inflammatory administration, GnRH antagonist protocols, reducing hCG dosage, replacement of hCG and in vitro maturation of oocytes (IVM). Conclusions Among the many prevention strategies that have been discussed, the current evidence points to the replacement of hCG by GnRH agonists in antagonist cycles and the performance of IVM procedures as the safest approaches.

AH was related to increased clinical pregnancy and multiple pregnancy rates in women with previous repeated failure or frozen-thawed embryos. However, AH is unlikely to increase clinical pregnancy rates when performed in fresh embryos transferred to unselected or non-poor prognosis women or to women of advanced age. Due to the small sample evaluated by the pool of included studies, no proper conclusions could be drawn regarding miscarriage or live birth.

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