Ovarian hyperstimulation syndrome: an endocrinopathy?

Ovarian hyperstimulation syndrome remains a significant but incompletely understood complication of ovarian stimulation. Evidence has accumulated regarding a role for various cytokines, in particular vascular endothelial growth factor, in its occurrence. However, the pathogenesis of ovarian hyperstimulation syndrome is likely to be complex and may involve a network of interacting cytokines and endocrine factors. Recent studies suggest links between specific cytokines and specific functional abnormalities in severe ovarian hyperstimulation syndrome. Two clinical forms of ovarian hyperstimulation syndrome may be distinguished, based on time of onset, with implications for the prediction and prevention of ovarian hyperstimulation syndrome in clinical practice.