In vitro fertilisation (IVF) techniques aim to generate multiple follicles (ovarian stimulation) from which to obtain eggs which will later be fertilised. The ovarian stimulation process culminates with the use of a drug which induces the final stage of egg maturation. The most commonly used one is human chorionic gonadotropin (hCG). This final step is essential in order to obtain eggs during ovarian puncture and it also indicates when the procedure should be carried out. The origin of empty follicle syndrome (EFS) is not fully understood and, when it occurs, no eggs are obtained following meticulous ovarian puncture, despite adequate follicle growth following ovarian stimulation and normal hormone results. […]