Abstract: Empty follicle syndrome（EFS）， which classified as “genuine” of “false”, is a rare complication of in vitro fertilization（IVF） treatment, leading to cycle cancellation. The underlying mechanism of the EFS remains hypothetical, such as low human chorionic gonadotropin（hCG） bioavailability, ovarian dysfunction and genetic factors. The risk of recurrence is higher as the age of the patients increases. Consequently, the diagnosis of EFS is retrospective while its treatment is difficult. Some false EFS patients could be rescued by repeating the hCG injection on the day of unsuccessful oocyte retrieval. The occurrence of genuine EFS will indicate poor IVF success in subsequent IVF cycles.

Key words: Chorionic gonadotropin, Estradiol, Prognosis, Empty follicle syndrome