Empty follicle syndrome: underlying etiology and precise treatment

With the use of assisted reproductive technology to treat infertility, there has been an increase in the condition known as empty follicle syndrome (EFS). EFS is characterized by the failure to retrieve oocytes from multiple mature follicles despite normal follicle development following ovarian stimulation. Despite its clinical significance, there is a lack of comprehensive and up-to-date reviews on this syndrome. In addition, the borderline form of EFS, that is characterized by low oocyte retrieval rates and is more common in clinical practice, has not been extensively discussed. This review aims to update perspectives on EFS, and covers its classification, etiology, treatment, prediction, prevention, and prognosis with the goal of leading to better clinical management and future research that improves outcomes for infertility patients.