Background: The ovarian hyperstimulation syndrome is a rare iatrogenic complication of ovarian stimulationoccurring during the luteal phase or during early pregnancy.
Case Report: A 32-year-old woman came to our department because of abdominal pain, after an ovulation induction by recombinant FSH and successful intrauterine insemination (IUI). The final diagnosis was critical ovarian hyperstimulation, arisen as a late type. Significant complications occurred, like multiple organ failure, hydrothorax, abdominal infection, ovarian necrosis, and haemolytic-uremic syndrome. The conservative surgery was impossible because of a wide ovarian infected necrosis .
Conclusions: Our case report presents the occurrence of an OHSS after IUI with a rFSH low dose stimulation, escorted by a series of severe complications. Our patient did not show PCOS. Abdominal paracentesis resulted in a precious diagnostic mean to detect the wide infection going on in the abdominal cavity. The infection occured spontaneously. Surgery was needed.

Keywords: OHSS, Multiple Organ Failure, ovarian necrosis