A complication of ovulation induction in infertility treatment. It is graded by the severity of symptoms which include ovary enlargement, multiple ovarian follicles; ovarian cysts; ascites; and generalized edema. The full-blown syndrome may lead to renal failure, respiratory distress, and even death. Increased capillary permeability is caused by the vasoactive substances, such as vascular endothelial growth factors, secreted by the overly-stimulated ovaries.