The Empty Follicle Syndrome (EFS) is a frustrating condition in which no oocytes (eggs) are retrieved at IVF, even though ultrasound and estradiol measurements showed the presence of many potential follicles.

The mechanism responsible for EFS remains obscure. Many hypotheses have been put forward, but none truly explain this syndrome. The most likely cause of EFS is ovarian ageing, as many patients who suffer from EFS are also poor responders.

If an EFS cycle does occur during your treatment, please make sure you discuss it thoroughly with your gynaecologist and the clinic counsellor.

EFS is an infrequent event and has been estimated to occur in between 2 – 7% of IVF cycles. However, the overall risk of recurrence in later IVF cycles is 20% and the risk of recurrence is higher as the age of the patient increases, with a risk of recurrence of <10% in patients <35 years, 24% for those between 35 and 39 years, and 57% for those over 40 years of age.