Efficacy and Safety of Dexamethasone Prevention for Patients of Ovarian Hyperstimulation Syndrome -- A Prospective, Randomized, Controlled Clinical Trial

Ovarian hyperstimulation syndrome (OHSS) is a iatrogenic complication of ovarian stimulation,which in its severe form is associated with significant morbidity and can be life threatening. It is characterized by cystic enlargement of the ovaries and rapid fluid shifts from the intravascular compartment to the third space. It is thought that increased vascular permeability is the pivotal mechanism of OHSS pathophysiology. The administration of human chorionic gonadotrophin results in the release of vasoactive substance such as vascular endothelial growth factor that causes vasodilation and leakage of fluids. Glucocorticoids and their synthetic derivatives have an inhibitory effect on the VEGF gene expression in vascular smooth muscle cells. By reducing leukocytic infiltration and the release of inflammatory mediator, inhibiting vasodilation and preventing increases in vascular permeability, these agents can dampen the inflammatory response and prevent edema formation ,thus offering a potential therapeutic intervention for OHSS. Investigators have observed more than a hundred patients in clinical practice that low-dose dexamethasone has prevention action for patients in IVF cycles at high risk of OHSS. This clinical trial is designed to evaluate the effect and security of dexamethasone prevention for patients of Ovarian Hyperstimulation Syndrome. There are two groups: bromocriptine group, dexamethasone group .After followed-up for 7 days , Clinical OHSS parameters will be collected at oocyte retrieval and at the 4rd d and 6th d of treatment .