ABSTRACT
The ovarian hyperstimulation syndrome (OHSS) is characterized by an increase in size of the ovaries, with the appearance of multiple cysts, and by an increase in the vascular perme ability of ovarian vessels causing ascites, pleural effusion and sometimes pericardiac effusion. The severe form is also accompanied by elec trolyte disturbances, as well as by cardio pulmonary, hepatic, renal and hemodynamic disturbances, leading to an increased thrombo embolic risk. The dominant finding is bilateral multicystic enlargement of the ovaries. Morpho logical examination of these ovaries reveals multiple corpora lutea, follicle cysts and mas sive edema of the ovarian stroma. It has been suggested that formation of the cysts is a direct reaction to stimulation with gonadotropins, since similar ovarian observations exist in other conditions associated with high levels of endogenous gonadotropins such as hydatidiform mole, choriocarcinoma and multiple pregnancy.