[Incidence of ovarian hyperstimulation syndrome in in-vitro-fertilization treatment over a period of 11 years].

A total of 2915 cycles of controlled ovarian hyperstimulation (COH) were performed from 1981 to 1992 in an in-vitro fertilization--embryo transfer (IVFET) programme at our institute. In 325 (11.2%) cycles an ovarian hyperstimulation syndrome (OHSS) developed. It was defined if more than 10 follicles with a size of > 15 mm were found on the day of follicle puncture. OHSS was found to be more frequent in the 3rd quarter of the years. Soltriol or melatonin may play a role in this context. Additionally, we were able to confirm some risk factors that were previously reported to be associated with the OHSS: use of gonadotropin-releasing hormone agonist (GnRHa) protocols, and young age (< 35 years). The pregnancy rate was found to be higher among OHSS cases.